杀念菌素/FR-008生物合成途径中多组份的产生机制以及二型硫脂酶的纠错功能
|
摘要
杀念菌素/ FR-008产自链霉菌FR-008(Streptomyces sp. FR-008)或灰色链霉菌IMRU3570(Streptomyces griseus IMRU 3570),是一种具有广谱抗真菌活性的七稀大环内酯类化合物。杀念菌素/FR-008复合物的原始组份主要包括FR-008-III,-V和-VI,而LC-MS以及NMR的证据显示组份FR-008-II,-I和-IV是由于原始组份分子结构C15-C19半缩醛键发生断裂而产生的衍生物。NMR结果确认三个原始组份的结构差异仅存在于糖苷配基亲水基团一侧:组份III和V在C-9位上携带羟基,而组份VI为C-9位亚甲基;组份III和VI在C-3位上为酮基,而组份V为C-3位羟基;此外,与存在于组份III和V上的C-5位亚甲基和C-13位羟基不同,组份VI所携带的C-5羟基和C-13位亚甲基不能与杀念菌素/FR-008聚酮链合成装配线上相应部分的功能域组成及排列相匹配,所以推测组份VI在聚酮延伸步骤16~(th)-20~(th)中经历了基团修饰功能域(KR, DH, ER)的非线性催化。根据杀念菌素/FR-008合成路径可以预测到:在聚酮延伸步骤18~(th)中功能域DH18的不完全活性可以导致C-9位羟基或亚甲基的产生,而最后一步聚酮延伸步骤中功能域KR21的不完全活性则可以造成C-3位上酮基或羟基的生成;此外,存在于杀念菌素/FR-008基因簇中的fscO基因所编码的单加氧酶也可能在后修饰步骤中负责C-9位羟基的生成。为了验证这些推论,首先对fscO基因进行了置换,结果发现fscO与杀念菌素/FR-008的生物合成途径没有关联。随后对DH18和KR21的活性位点进行定点突变后得到了惊喜的结果:突变DH18使得携带C-9位亚甲基的组份VI不再积累,而携带C-9位羟基的组份III和V仍正常积累;突变KR21使得携带C-3位羟基的组份V不再积累,而携带C-3位酮基的组份III和VI仍正常积累;同时突变DH18和KR21则导致组份V和VI的积累同时丧失,而携带C-3位酮基和C-9位羟基的组份III仍正常积累。至此,根据化学结构解析以及遗传突变结果可以断定三个杀念菌素/FR-008主要组份的结构分化主要是由DH18和KR21的非完全活性所导致。此外,抑菌活性实验显示组份III的活性大于V而与VI相当。另外,组份III的水溶性优于VI,所以相对于V和VI,组份III的药用价值更为显著。因此,定向积累组份III的突变株ZYJ-6 (DH18和KR21双突变)具有显著的应用价值。KR,DH和ER是负责聚酮链延伸过程中基团修饰的功能域,是聚酮产物碳链母环上功能基团多样性以及分子异构化的基础,有效地操控这些功能域的催化活性可创造出更多新结构衍生物,作为新药筛选的基础。
二型硫酯酶(TEII)与一型硫脂酶(TEI)的显著区别在于:前者作为一个单独的蛋白行使硫脂键水解功能,而后者作为聚酮合酶(PKS)或非核糖体聚肽合酶(NRPS)碳端的一个功能域行使催化活性。在PKS和NRPS的基因簇中广泛存在着TEII编码基因。TEII基因的缺失导致聚酮或聚肽的产量显著降低,从而预示TEII与产物的合成效率相关。已有生化证据显示TEII可以水解去除ACP或PCP上加载的不能被聚酮或聚肽链延伸所利用的底物。但是还没有令人信服的数据来确证TEII在聚酮合成过程中的底物选择性,即TEII选择性的水解清除不能被PKS脱羧聚合反应所利用的中间产物而不去水解破坏正常的PKS延伸单位。
作为典型的一型PKS合成途径,杀念菌素/FR-008合成基因簇中也存在TEII编码基因fscTE。链霉菌FR-008拥有成熟的遗传操作工艺,可观的产素水平以及快速的生长特性,所以是研究PKS合成途径中TEII功能的理想材料。首先发现对fscTE的同框缺失后杀念菌素/FR-008产量下降了约90%;用fscTE在组成型启动子(ermE*p)下回补该突变株后产素水平得到显著恢复(75%);作为回补实验对照,活性位点突变后的fscTE(S129A)不能恢复产素水平,从而确认了FscTE的催化活性与杀念菌素/FR-008聚酮的合成效率密切相关。为了验证PKS途径中TEII的底物特异性,在FscTE氮端加载组氨酸标记后在大肠杆菌中对其进行高表达并最终纯化得到了高纯度的FscTE重组蛋白。SNAC衍生物作为酰基化载体蛋白(ACP或PCP)的模拟物已被成功的应用于硫脂酶催化机理的研究中。在本实验中乙酸和丙酸的氮-乙酰半胱胺硫脂(SNAC)衍生物被用来模拟加载于ACP上的不能被聚酮延伸所利用的中间产物,而丙二酸和甲基丙二酸的SNAC衍生物被用来模拟加载于ACP上的正常的聚酮延伸单位。体外酶催化实验表明FscTE对乙酸和丙酸的硫脂键具有显著的水解活性,而对丙二酸和甲基丙二酸的硫脂键仅有痕量的水解活性。这间接的证明了TEII选择性的水解清除加载于ACP上的不能被聚酮脱羧聚合延伸反应所利用的中间产物,而极少去干扰正常的延伸单位。为了更充分的确认这个结论,另一个PKS途径的TEII,即来自泰勒菌素(tylosin)的TylO,也被高效表达并纯化后用来对以上SNAC底物作测试。结果表明:TylO与FscTE的底物特异性完全一致。此外,对氨基苯甲酸SNAC也被用来模拟加载于ACP上的杀念菌素/FR-008合成起始单位。结果FscTE对对氨基苯甲酸SNAC硫脂键仅有痕量的水解活性。这提示FscTE不干扰杀念菌素/FR-008聚酮合成的起始。在链霉菌FR-008中导入额外拷贝的fscTE(在ermE*p启动下)并没有造成杀念菌素/FR-008产量的下降,从而在另一个角度暗示FscTE仅清除不能被延伸利用的中间物,而不干扰聚酮合成的正常进行。
目前普遍认为TEII在PKS合成过程中不参与聚酮链的最终释放,即TEII不能代替TEI的角色而负责延伸链的最终释放,这主要是基于两点体外生化实验证据:(一)体外实验显示TEII对长链聚酮硫脂键的水解活性很低;(二)大量的体外生化实验证明TEI可以有效的水解长链聚酮化合物的硫脂键。但是尚未有遗传学证据来支持这一观点。于是,对杀念菌素/FR-008聚酮合酶FscF碳端所携带的TEI功能域的活性位点进行了突变(S1887A和S1888A),结果TEI失去活性后导致杀念菌素/FR-008不再积累。这表明TEI的催化活性对于杀念菌素/FR-008聚酮链的最终释放是必不可少的,TEII无法替代TEI的使命。
源自PKS和NRPS途径的TEII在进化上的差别也在杀念菌素/FR-008合成系统中得到了体现。属于PKS系统的TEII基因(tylO)可以部分的回补fscTE缺失突变株,而另外两个NRPS系统的TEII基因(tycF和srfAD)不能回补该突变株。这很好的呼应了已报道的生化实验结果:即源自NRPS的TEII只能识别PCP而不能作用于ACP,而源自PKS的TEII可识别不同来源的ACP。此外,TylO能促进FR-008合成效率的证据与其体外试验底物选择特性的结果形成了很好的呼应,从而更为坚实的支持了这样一个命题:“TEII选择性的清除错误的中间产物,从而确保了杀念菌素/FR-008聚酮合成的高效运行”。
FR-008/candicidin, a heptaene macrolide with antifungal activity, is produced by Streptomyces sp. FR-008 or Streptomyces griseus IMRU3570. Three compounds, FR-008-III, -V, and -VI, represent the natural components of FR-008/candicidin mixture. The other three compounds, FR-008-II, -1, and -IV, were identified, based LC-MS and NMR analysis, as the products respectively converted from the component III, V, and VI as the opening of hemiketal ring between C-15 and C-19 in FR-008/candicidin aglycone. FR-008-III, -V, and -VI were characterized by NMR, and the difference of their chemical structure lies in the group variations in polyol region of aglycone, in which III and V have C-9 hydroxyl, while C-9 methylene presents in VI; III and VI have C-3 ketone, while V carries C-3 hydroxyl; compared to the C-5 methylene and C-13 hydroxyl in III and V, component VI bears C-5 hydroxyl and C-13 methylene, which is unexpected according to the domains organization in polyketid assembly 16~(th)-20~(th), and assumed to be resulted in by a untypical program of group modifying by functional domain KR, DH, and ER. According to FR-008/candicidin polyketide assembly line, coexistence of ketone or hydroxyl at C-3, and also methylene or hydroxyl at C-9 in FR-008 aglycone could be generated respectively as the incomplete activities of KR21 and DH18 during polyketide biosynthesis. Additionally, one monooxygenase, encoded by fscO localized at the left end of the FR-008 gene cluster, was assumed as a candidate for restoring C-9 hydroxyl at tailoring modification step. For exploring the hypothesis above, fscO was firstly knocked out and proved to be irrelevant to group variations in FR-008/candicidin. Subsequently, the site-directed mutagenesis analysis of DH18 and KR21 brought out exciting result: inactivation of KR21and DH18 respectively abolished production of component V carrying a C-3 hydroxyl, and VI carrying a C-9 methylene, while combined mutagenesis of KR21 and DH18 created a mutant producing only III, with a C-3 ketone and a C-9 hydroxyl. Incomplete activities of KR21 and DH18 were, therefore, unambiguously identified to be directly involved in co-production of three FR-008 analogues. Furthermore, bioassay analysis indicated component III having the antifungal activity superior to V and comparable to VI. Plus better water-solubility of component III than VI, III appeared to be excellent in pharmacological properties. The mutant ZYJ-6 (combined mutation of KR21 and DH18) singly accumulating component III, therefore, has a distinctive significance of industry application. DH, KR, or ER domains playing as modification domains in PKS contributed basically to the group variations in the carbon frame-work of polyketid product. The modification domains in a PKS can be manipulated effectively to generate series of structural derivatives provided for superior drugs screening.
Type I thioesterase (TEI) functions as a catalysis domain fused at the C-terminal of PKS/NRPS assembly protein, while the type II thioesterase (TEII) plays its role as a discrete protein. TEIIs were also found within many type I PKSs and NRPS gene clusters. Disruption of the TEII genes was documented to greatly reduce product yields and thus implying TEII crucial to efficiency of product biosynthesis. Biochemical evidences indicate TEII can remove the nonelongatable substrates bond to ACP or PCP. However, no convince evidence, hitherto, revealed TEII with a capability of selectively removing the nonelongatable residues from the unprocessed PKS proteins, and thus ensuring efficient polyketide biosynthesis.
One TEII gene (fscTE) was also found in FR-008/candicidin gene cluster encoding a typical type I PKS biosynthetic pathway. Streptomyces sp. FR-008 is an excellent material for researching on TEII as its convenient genetic manipulation, high yield metabolites production, and short growth-period. Deletion of fscTE reduced approximately 90 % of the FR-008/candicidin production, while the production level was well restored (75%) when fscTE constructively promoted by ermE*p was added back to the mutant in trans. As a negative control of complementation, the mutated fscTE (S129A) was also introduced to the mutant and identified to have no contribution to production restoring, and therefore revealed that the activity of FscTE was crucial to effective FR-008 polyketide biosynthesis. To explore the substrate specificities of TEII in PKS, The FscTE was expressed as a fusion protein tagged with an N-terminal hexa-histidine and purified to homogeneity. As the N-acetylcysteamine thioester (SNAC) well used as the model substrates of the acyl chains bound to the phosphopantetheine arm of the ACP/or PCP in thioesterase hydrolysis assays, acetyl-SNAC and propionyl-SNAC, in this study, were prepared to mimic the aberrant acyl-ACP substrates, and malonyl-SNAC and methylmalonyl-SNAC were used to represent the correct substrates in PKS condensing reaction. Direct biochemical analysis demonstrated FscTE with remarkable preferences of hydrolyzing acyl-thioesters, i.e. propionyl-SNAC over methylmalonyl-SNAC and acetyl-SNAC over malonyl-SNAC, and thus concluded that TEII could maintain effective polyketide biosynthesis by selectively removing the nonelongatable residues bound to ACPs. For further confirming the substrate recognition of TEII, another well described PKS TEII (TylO) from tylosin biosynthetic pathway was also expressed and tested using the same SNAC substrates, and proved to have the same substrates specificities as that of FscTE. Moreover, p-aminobenzoyl-SNAC was also prepared to model the p-aminobenzoyl-ACP substrate in initiation of FR-008/candicidin biosynthesis. Only low hydrolysis activity of FscTE on p-aminobenzoyl-SNAC was detected, and hereby ruled out the possible involvement of FscTE in the initiation of FR-008/candicidin biosynthesis.
High level of FscTE expression by introducing extra copy of fscTE under constructive promoter ermE*p did not suppress Candicidin/FR-008 formation, and thus supporting the notion that FscTE only specifically removed the aberrant residues from ACP rather than disturbed the normal process.
TEIIs were generally believed not to be involved in releasing of maturely elongated chain mainly based on the biochemical evidences that TEIIs possess very low hydrolysis activities to long chain thioesters of polyketide or polypeptide, while the excised TEI domain can self-efficiently do the work. Considering no genetic evidences support the opinion that TEII can not substitute TEI for chain terminal release, the TEI domain in FscF was inactivated by site-directed mutagenesis (S1887A & S1888A). The TEI mutation resulted in total disruption of Candicidin/FR-008 production, and thus implied that TEII can not exert TEI’s role for terminal release.
Furthermore, the evolutionary distance between the TEIIs from PKS and NRPS was reflected distinctively by their different complementation efficiencies to the fscTE mutant, in which the PKS-type TEII tylO can partially restore FR-008/candididin production (30%), and the NRPS-type TEII tycF and srfAD were proved to be idle. The result is well correspondent to the documented biochemical evidences, in which NRPS-type TEII can only recognize PCP but not ACP, and PKS-type TEII can recognize the ACPs of different origins. Furthermore, the evidence of TylO improving Candicidin/FR-008 biosynthesis is well consistent to the substrate specificities of TylO in vitro, and further supporting the conclusion: type I1 thioesterase ensures efficient polyketide biosynthesis by selectively removing the aberrant extender units.
二型硫酯酶(TEII)与一型硫脂酶(TEI)的显著区别在于:前者作为一个单独的蛋白行使硫脂键水解功能,而后者作为聚酮合酶(PKS)或非核糖体聚肽合酶(NRPS)碳端的一个功能域行使催化活性。在PKS和NRPS的基因簇中广泛存在着TEII编码基因。TEII基因的缺失导致聚酮或聚肽的产量显著降低,从而预示TEII与产物的合成效率相关。已有生化证据显示TEII可以水解去除ACP或PCP上加载的不能被聚酮或聚肽链延伸所利用的底物。但是还没有令人信服的数据来确证TEII在聚酮合成过程中的底物选择性,即TEII选择性的水解清除不能被PKS脱羧聚合反应所利用的中间产物而不去水解破坏正常的PKS延伸单位。
作为典型的一型PKS合成途径,杀念菌素/FR-008合成基因簇中也存在TEII编码基因fscTE。链霉菌FR-008拥有成熟的遗传操作工艺,可观的产素水平以及快速的生长特性,所以是研究PKS合成途径中TEII功能的理想材料。首先发现对fscTE的同框缺失后杀念菌素/FR-008产量下降了约90%;用fscTE在组成型启动子(ermE*p)下回补该突变株后产素水平得到显著恢复(75%);作为回补实验对照,活性位点突变后的fscTE(S129A)不能恢复产素水平,从而确认了FscTE的催化活性与杀念菌素/FR-008聚酮的合成效率密切相关。为了验证PKS途径中TEII的底物特异性,在FscTE氮端加载组氨酸标记后在大肠杆菌中对其进行高表达并最终纯化得到了高纯度的FscTE重组蛋白。SNAC衍生物作为酰基化载体蛋白(ACP或PCP)的模拟物已被成功的应用于硫脂酶催化机理的研究中。在本实验中乙酸和丙酸的氮-乙酰半胱胺硫脂(SNAC)衍生物被用来模拟加载于ACP上的不能被聚酮延伸所利用的中间产物,而丙二酸和甲基丙二酸的SNAC衍生物被用来模拟加载于ACP上的正常的聚酮延伸单位。体外酶催化实验表明FscTE对乙酸和丙酸的硫脂键具有显著的水解活性,而对丙二酸和甲基丙二酸的硫脂键仅有痕量的水解活性。这间接的证明了TEII选择性的水解清除加载于ACP上的不能被聚酮脱羧聚合延伸反应所利用的中间产物,而极少去干扰正常的延伸单位。为了更充分的确认这个结论,另一个PKS途径的TEII,即来自泰勒菌素(tylosin)的TylO,也被高效表达并纯化后用来对以上SNAC底物作测试。结果表明:TylO与FscTE的底物特异性完全一致。此外,对氨基苯甲酸SNAC也被用来模拟加载于ACP上的杀念菌素/FR-008合成起始单位。结果FscTE对对氨基苯甲酸SNAC硫脂键仅有痕量的水解活性。这提示FscTE不干扰杀念菌素/FR-008聚酮合成的起始。在链霉菌FR-008中导入额外拷贝的fscTE(在ermE*p启动下)并没有造成杀念菌素/FR-008产量的下降,从而在另一个角度暗示FscTE仅清除不能被延伸利用的中间物,而不干扰聚酮合成的正常进行。
目前普遍认为TEII在PKS合成过程中不参与聚酮链的最终释放,即TEII不能代替TEI的角色而负责延伸链的最终释放,这主要是基于两点体外生化实验证据:(一)体外实验显示TEII对长链聚酮硫脂键的水解活性很低;(二)大量的体外生化实验证明TEI可以有效的水解长链聚酮化合物的硫脂键。但是尚未有遗传学证据来支持这一观点。于是,对杀念菌素/FR-008聚酮合酶FscF碳端所携带的TEI功能域的活性位点进行了突变(S1887A和S1888A),结果TEI失去活性后导致杀念菌素/FR-008不再积累。这表明TEI的催化活性对于杀念菌素/FR-008聚酮链的最终释放是必不可少的,TEII无法替代TEI的使命。
源自PKS和NRPS途径的TEII在进化上的差别也在杀念菌素/FR-008合成系统中得到了体现。属于PKS系统的TEII基因(tylO)可以部分的回补fscTE缺失突变株,而另外两个NRPS系统的TEII基因(tycF和srfAD)不能回补该突变株。这很好的呼应了已报道的生化实验结果:即源自NRPS的TEII只能识别PCP而不能作用于ACP,而源自PKS的TEII可识别不同来源的ACP。此外,TylO能促进FR-008合成效率的证据与其体外试验底物选择特性的结果形成了很好的呼应,从而更为坚实的支持了这样一个命题:“TEII选择性的清除错误的中间产物,从而确保了杀念菌素/FR-008聚酮合成的高效运行”。
FR-008/candicidin, a heptaene macrolide with antifungal activity, is produced by Streptomyces sp. FR-008 or Streptomyces griseus IMRU3570. Three compounds, FR-008-III, -V, and -VI, represent the natural components of FR-008/candicidin mixture. The other three compounds, FR-008-II, -1, and -IV, were identified, based LC-MS and NMR analysis, as the products respectively converted from the component III, V, and VI as the opening of hemiketal ring between C-15 and C-19 in FR-008/candicidin aglycone. FR-008-III, -V, and -VI were characterized by NMR, and the difference of their chemical structure lies in the group variations in polyol region of aglycone, in which III and V have C-9 hydroxyl, while C-9 methylene presents in VI; III and VI have C-3 ketone, while V carries C-3 hydroxyl; compared to the C-5 methylene and C-13 hydroxyl in III and V, component VI bears C-5 hydroxyl and C-13 methylene, which is unexpected according to the domains organization in polyketid assembly 16~(th)-20~(th), and assumed to be resulted in by a untypical program of group modifying by functional domain KR, DH, and ER. According to FR-008/candicidin polyketide assembly line, coexistence of ketone or hydroxyl at C-3, and also methylene or hydroxyl at C-9 in FR-008 aglycone could be generated respectively as the incomplete activities of KR21 and DH18 during polyketide biosynthesis. Additionally, one monooxygenase, encoded by fscO localized at the left end of the FR-008 gene cluster, was assumed as a candidate for restoring C-9 hydroxyl at tailoring modification step. For exploring the hypothesis above, fscO was firstly knocked out and proved to be irrelevant to group variations in FR-008/candicidin. Subsequently, the site-directed mutagenesis analysis of DH18 and KR21 brought out exciting result: inactivation of KR21and DH18 respectively abolished production of component V carrying a C-3 hydroxyl, and VI carrying a C-9 methylene, while combined mutagenesis of KR21 and DH18 created a mutant producing only III, with a C-3 ketone and a C-9 hydroxyl. Incomplete activities of KR21 and DH18 were, therefore, unambiguously identified to be directly involved in co-production of three FR-008 analogues. Furthermore, bioassay analysis indicated component III having the antifungal activity superior to V and comparable to VI. Plus better water-solubility of component III than VI, III appeared to be excellent in pharmacological properties. The mutant ZYJ-6 (combined mutation of KR21 and DH18) singly accumulating component III, therefore, has a distinctive significance of industry application. DH, KR, or ER domains playing as modification domains in PKS contributed basically to the group variations in the carbon frame-work of polyketid product. The modification domains in a PKS can be manipulated effectively to generate series of structural derivatives provided for superior drugs screening.
Type I thioesterase (TEI) functions as a catalysis domain fused at the C-terminal of PKS/NRPS assembly protein, while the type II thioesterase (TEII) plays its role as a discrete protein. TEIIs were also found within many type I PKSs and NRPS gene clusters. Disruption of the TEII genes was documented to greatly reduce product yields and thus implying TEII crucial to efficiency of product biosynthesis. Biochemical evidences indicate TEII can remove the nonelongatable substrates bond to ACP or PCP. However, no convince evidence, hitherto, revealed TEII with a capability of selectively removing the nonelongatable residues from the unprocessed PKS proteins, and thus ensuring efficient polyketide biosynthesis.
One TEII gene (fscTE) was also found in FR-008/candicidin gene cluster encoding a typical type I PKS biosynthetic pathway. Streptomyces sp. FR-008 is an excellent material for researching on TEII as its convenient genetic manipulation, high yield metabolites production, and short growth-period. Deletion of fscTE reduced approximately 90 % of the FR-008/candicidin production, while the production level was well restored (75%) when fscTE constructively promoted by ermE*p was added back to the mutant in trans. As a negative control of complementation, the mutated fscTE (S129A) was also introduced to the mutant and identified to have no contribution to production restoring, and therefore revealed that the activity of FscTE was crucial to effective FR-008 polyketide biosynthesis. To explore the substrate specificities of TEII in PKS, The FscTE was expressed as a fusion protein tagged with an N-terminal hexa-histidine and purified to homogeneity. As the N-acetylcysteamine thioester (SNAC) well used as the model substrates of the acyl chains bound to the phosphopantetheine arm of the ACP/or PCP in thioesterase hydrolysis assays, acetyl-SNAC and propionyl-SNAC, in this study, were prepared to mimic the aberrant acyl-ACP substrates, and malonyl-SNAC and methylmalonyl-SNAC were used to represent the correct substrates in PKS condensing reaction. Direct biochemical analysis demonstrated FscTE with remarkable preferences of hydrolyzing acyl-thioesters, i.e. propionyl-SNAC over methylmalonyl-SNAC and acetyl-SNAC over malonyl-SNAC, and thus concluded that TEII could maintain effective polyketide biosynthesis by selectively removing the nonelongatable residues bound to ACPs. For further confirming the substrate recognition of TEII, another well described PKS TEII (TylO) from tylosin biosynthetic pathway was also expressed and tested using the same SNAC substrates, and proved to have the same substrates specificities as that of FscTE. Moreover, p-aminobenzoyl-SNAC was also prepared to model the p-aminobenzoyl-ACP substrate in initiation of FR-008/candicidin biosynthesis. Only low hydrolysis activity of FscTE on p-aminobenzoyl-SNAC was detected, and hereby ruled out the possible involvement of FscTE in the initiation of FR-008/candicidin biosynthesis.
High level of FscTE expression by introducing extra copy of fscTE under constructive promoter ermE*p did not suppress Candicidin/FR-008 formation, and thus supporting the notion that FscTE only specifically removed the aberrant residues from ACP rather than disturbed the normal process.
TEIIs were generally believed not to be involved in releasing of maturely elongated chain mainly based on the biochemical evidences that TEIIs possess very low hydrolysis activities to long chain thioesters of polyketide or polypeptide, while the excised TEI domain can self-efficiently do the work. Considering no genetic evidences support the opinion that TEII can not substitute TEI for chain terminal release, the TEI domain in FscF was inactivated by site-directed mutagenesis (S1887A & S1888A). The TEI mutation resulted in total disruption of Candicidin/FR-008 production, and thus implied that TEII can not exert TEI’s role for terminal release.
Furthermore, the evolutionary distance between the TEIIs from PKS and NRPS was reflected distinctively by their different complementation efficiencies to the fscTE mutant, in which the PKS-type TEII tylO can partially restore FR-008/candididin production (30%), and the NRPS-type TEII tycF and srfAD were proved to be idle. The result is well correspondent to the documented biochemical evidences, in which NRPS-type TEII can only recognize PCP but not ACP, and PKS-type TEII can recognize the ACPs of different origins. Furthermore, the evidence of TylO improving Candicidin/FR-008 biosynthesis is well consistent to the substrate specificities of TylO in vitro, and further supporting the conclusion: type I1 thioesterase ensures efficient polyketide biosynthesis by selectively removing the aberrant extender units.
引文
1. Admiraal, S. J., C. T. Walsh, and C. Khosla. 2001. The loading module of rifamycin synthetase is an adenylation-thiolation didomain with substrate tolerance for substituted benzoates. Biochemistry 40:6116-23.
2. Anton, N., M. V. Mendes, J. F. Martin, and J. F. Aparicio. 2004. Identification of PimR as a positive regulator of pimaricin biosynthesis in Streptomyces natalensis. J Bacteriol 186:2567-75.
3. Aparicio, J. F., P. Caffrey, J. A. Gil, and S. B. Zotchev. 2003. Polyene antibiotic biosynthesis gene clusters. Appl Microbiol Biotechnol 61:179-88.
4. Aparicio, J. F., R. Fouces, M. V. Mendes, N. Olivera, and J. F. Martin. 2000. A complex multienzyme system encoded by five polyketide synthase genes is involved in the biosynthesis of the 26-membered polyene macrolide pimaricin in Streptomyces natalensis. Chem Biol 7:895-905.
5. Aparicio, J. F., M. V. Mendes, N. Anton, E. Recio, and J. F. Martin. 2004. Polyene macrolide antibiotic biosynthesis. Curr Med Chem 11:1645-56.
6. Bentley, S. D., S. Brown, L. D. Murphy, D. E. Harris, M. A. Quail, J. Parkhill, B. G. Barrell, J. R. McCormick, R. I. Santamaria, R. Losick, M. Yamasaki, H. Kinashi, C. W. Chen, G. Chandra, D. Jakimowicz, H. M. Kieser, T. Kieser, and K. F. Chater. 2004. SCP1, a 356,023 bp linear plasmid adapted to the ecology and developmental biology of its host, Streptomyces coelicolor A3(2). Mol Microbiol 51:1615-28.
7. Bentley, S. D., K. F. Chater, A. M. Cerdeno-Tarraga, G. L. Challis, N. R. Thomson, K. D. James, D. E. Harris, M. A. Quail, H. Kieser, D. Harper, A. Bateman, S. Brown, G. Chandra, C. W. Chen, M. Collins, A. Cronin, A. Fraser, A. Goble, J. Hidalgo, T. Hornsby, S. Howarth, C. H. Huang, T. Kieser, L. Larke, L. Murphy, K. Oliver, S. O'Neil, E. Rabbinowitsch, M. A. Rajandream, K. Rutherford, S. Rutter, K. Seeger, D. Saunders, S. Sharp, R. Squares, S. Squares, K. Taylor, T. Warren, A. Wietzorrek, J. Woodward, B. G. Barrell, J. Parkhill, and D. A. Hopwood. 2002. Complete genome sequence of the model actinomycete Streptomyces coelicolor A3(2). Nature 417:141-7.
8. Birch, A., A. Hausler, and R. Hutter. 1990. Genome rearrangement and genetic instability in Streptomyces spp. J Bacteriol 172:4138-42.
9. Blatch, G. L., and M. Lassle. 1999. The tetratricopeptide repeat: a structural motif mediating protein-protein interactions. Bioessays 21:932-9.
10. Borgos, S. E., H. Sletta, E. Fjaervik, T. Brautaset, T. E. Ellingsen, O. M. Gulliksen, and S. B. Zotchev. 2006. Effect of glucose limitation and specific mutations in the module 5 enoyl reductase domains in the nystatin and amphotericin polyketide synthases on polyene macrolide biosynthesis. Arch Microbiol 185:165-71.
11. Borgos, S. E., P. Tsan, H. Sletta, T. E. Ellingsen, J. M. Lancelin, and S. B. Zotchev. 2006. Probing the structure-function relationship of polyene macrolides: engineered biosynthesis of soluble nystatin analogues. J Med Chem 49:2431-9.
12. Brautaset, T., S. E. Borgos, H. Sletta, T. E. Ellingsen, and S. B. Zotchev. 2003.Site-specific mutagenesis and domain substitutions in the loading module of the nystatin polyketide synthase, and their effects on nystatin biosynthesis in Streptomyces noursei. J Biol Chem 278:14913-9.
13. Brautaset, T., O. N. Sekurova, H. Sletta, T. E. Ellingsen, A. R. StrLm, S. Valla, and S. B. Zotchev. 2000. Biosynthesis of the polyene antifungal antibiotic nystatin in Streptomyces noursei ATCC 11455: analysis of the gene cluster and deduction of the biosynthetic pathway. Chem Biol 7:395-403.
14. Brodhagen, M., I. Paulsen, and J. E. Loper. 2005. Reciprocal regulation of pyoluteorin production with membrane transporter gene expression in Pseudomonas fluorescens Pf-5. Appl Environ Microbiol 71:6900-9.
15. Bruheim, P., S. E. Borgos, P. Tsan, H. Sletta, T. E. Ellingsen, J. M. Lancelin, and S. B. Zotchev. 2004. Chemical diversity of polyene macrolides produced by Streptomyces noursei ATCC 11455 and recombinant strain ERD44 with genetically altered polyketide synthase NysC. Antimicrob Agents Chemother 48:4120-9.
16. Butler, A. R., N. Bate, and E. Cundliffe. 1999. Impact of thioesterase activity on tylosin biosynthesis in Streptomyces fradiae. Chem Biol 6:287-92.
17. Byrne, B., M. Carmody, E. Gibson, B. Rawlings, and P. Caffrey. 2003. Biosynthesis of deoxyamphotericins and deoxyamphoteronolides by engineered strains of Streptomyces nodosus. Chem Biol 10:1215-24.
18. Caffrey, P., J. F. Aparicio, F. Malpartida, and S. B. Zotchev. 2008. Biosynthetic engineering of polyene macrolides towards generation of improved antifungal and antiparasitic agents. Curr Top Med Chem 8:639-53.
19. Caffrey, P., S. Lynch, E. Flood, S. Finnan, and M. Oliynyk. 2001. Amphotericin biosynthesis in Streptomyces nodosus: deductions from analysis of polyketide synthase and late genes. Chem Biol 8:713-23.
20. Campelo, A. B., and J. A. Gil. 2002. The candicidin gene cluster from Streptomyces griseus IMRU 3570. Microbiology 148:51-9.
21. Carmody, M., B. Murphy, B. Byrne, P. Power, D. Rai, B. Rawlings, and P. Caffrey. 2005. Biosynthesis of amphotericin derivatives lacking exocyclic carboxyl groups. J Biol Chem 280:34420-6.
22. Chalut, C., L. Botella, C. de Sousa-D'Auria, C. Houssin, and C. Guilhot. 2006. The nonredundant roles of two 4'-phosphopantetheinyl transferases in vital processes of Mycobacteria. Proc Natl Acad Sci U S A 103:8511-6.
23. Chater, K. F. 1992. Genetic regulation of secondary metabolic pathways in Streptomyces. Ciba Found Symp 171:144-56; discussion 156-62.
24. Chen, S., X. Huang, X. Zhou, L. Bai, J. He, K. J. Jeong, S. Y. Lee, and Z. Deng. 2003. Organizational and mutational analysis of a complete FR-008/candicidin gene cluster encoding a structurally related polyene complex. Chem Biol 10:1065-76.
25. Chen, S., J. B. Roberts, Y. Xue, D. H. Sherman, and K. A. Reynolds. 2001. The Streptomyces venezuelae pikAV gene contains a transcription unit essential for expression of enzymes involved in glycosylation of narbonolide and 10-deoxymethynolide. Gene 263:255-64.
26. Cundliffe, E., N. Bate, A. Butler, S. Fish, A. Gandecha, and L. Merson-Davies. 2001. The tylosin-biosynthetic genes of Streptomyces fradiae. Antonie Van Leeuwenhoek 79:229-34.
27. Del Vecchio, F., H. Petkovic, S. G. Kendrew, L. Low, B. Wilkinson, R. Lill, J. Cortes, B. A. Rudd, J. Staunton, and P. F. Leadlay. 2003. Active-site residue, domain and module swaps in modular polyketide synthases. J Ind Microbiol Biotechnol 30:489-94.
28. Doi-Katayama, Y., Y. J. Yoon, C. Y. Choi, T. W. Yu, H. G. Floss, and C. R. Hutchinson. 2000. Thioesterases and the premature termination of polyketide chain elongation in rifamycin B biosynthesis by Amycolatopsis mediterranei S699. J Antibiot (Tokyo) 53:484-95.
29. Enquist M, B. 1971. Characterization of deoxyribonucleic acid from Streptomyces venezulae spores. Dev Ind Microbiol 12:225-236.
30. Fischbach, M. A., and C. T. Walsh. 2006. Assembly-line enzymology for polyketide and nonribosomal Peptide antibiotics: logic, machinery, and mechanisms. Chem Rev 106:3468-96.
31. Fischl, A. S., and E. P. Kennedy. 1990. Isolation and properties of acyl carrier protein phosphodiesterase of Escherichia coli. J Bacteriol 172:5445-9.
32. Geoffroy, V. A., J. D. Fetherston, and R. D. Perry. 2000. Yersinia pestis YbtU and YbtT are involved in synthesis of the siderophore yersiniabactin but have different effects on regulation. Infect Immun 68:4452-61.
33. Gokhale, R. S., D. Hunziker, D. E. Cane, and C. Khosla. 1999. Mechanism and specificity of the terminal thioesterase domain from the erythromycin polyketide synthase. Chem Biol 6:117-25.
34. Guimond, J., and R. Morosoli. 2008. Identification of Streptomyces lividans proteins secreted by the twin-arginine translocation pathway following growth with different carbon sources. Can J Microbiol 54:549-58.
35. Harvey, B. M., H. Hong, M. A. Jones, Z. A. Hughes-Thomas, R. M. Goss, M. L. Heathcote, V. M. Bolanos-Garcia, W. Kroutil, J. Staunton, P. F. Leadlay, and J. B. Spencer. 2006. Evidence that a novel thioesterase is responsible for polyketide chain release during biosynthesis of the polyether ionophore monensin. Chembiochem 7:1435-42.
36. Heathcote, M. L., J. Staunton, and P. F. Leadlay. 2001. Role of type II thioesterases: evidence for removal of short acyl chains produced by aberrant decarboxylation of chain extender units. Chem Biol 8:207-20.
37. Hopwood, D. A. 1999. Forty years of genetics with Streptomyces: from in vivo through in vitro to in silico. Microbiology 145 ( Pt 9):2183-202.
38. Hopwood, D. A. 1997. Genetic Contributions to Understanding Polyketide Synthases. Chem Rev 97:2465-2498.
39. Hopwood, D. A., M. J. Bibb, K. F. Chater, T. Kieser, C. J. Bruton, H. M. Kieser, D. J. Lydiate, C. P. Smith, J. M. Ward, and H. Schrempf. 1985. Genetic Manipulation of Streptomyces-A Laboratory Manual. The John Innes Foundation, Norwich.
40. Hu, Z., K. Bao, X. Zhou, Q. Zhou, D. A. Hopwood, T. Kieser, and Z. Deng. 1994. Repeated polyketide synthase modules involved in the biosynthesis of a heptaene macrolide by Streptomyces sp. FR-008. Mol Microbiol 14:163-72.
41. Hu, Z., B. A. Pfeifer, E. Chao, S. Murli, J. Kealey, J. R. Carney, G. Ashley, C. Khosla, and C. R. Hutchinson. 2003. A specific role of the Saccharopolyspora erythraea thioesterase II gene in the function of modular polyketide synthases. Microbiology 149:2213-25.
42. Huang, Y., E. Wendt-Pienkowski, and B. Shen. 2006. A dedicated phosphopantetheinyl transferase for the fredericamycin polyketide synthase from Streptomyces griseus. J Biol Chem 281:29660-8.
43. Ikeda, H., T. Nonomiya, and S. Omura. 2001. Organization of biosynthetic gene cluster for avermectin in Streptomyces avermitilis: analysis of enzymatic domains in four polyketide synthases. J Ind Microbiol Biotechnol 27:170-6.
44. Ikeda, H., T. Nonomiya, M. Usami, T. Ohta, and S. Omura. 1999. Organization of the biosynthetic gene cluster for the polyketide anthelmintic macrolide avermectin in Streptomyces avermitilis. Proc Natl Acad Sci U S A 96:9509-14.
45. Janssen, G. R., and M. J. Bibb. 1993. Derivatives of pUC18 that have BglII sites flanking a modified multiple cloning site and that retain the ability to identify recombinant clones by visual screening of Escherichia coli colonies. Gene 124:133-134.
46. Jung, W. S., S. K. Lee, J. S. Hong, S. R. Park, S. J. Jeong, A. R. Han, J. K. Sohng, B. G. Kim, C. Y. Choi, D. H. Sherman, and Y. J. Yoon. 2006. Heterologous expression of tylosin polyketide synthase and production of a hybrid bioactive macrolide in Streptomyces venezuelae. Appl Microbiol Biotechnol 72:763-9.
47. Khosla, C., Y. Tang, A. Y. Chen, N. A. Schnarr, and D. E. Cane. 2007. Structure and mechanism of the 6-deoxyerythronolide B synthase. Annu Rev Biochem 76:195-221.
48. Kieser, T., Bibb, M.J., Buttner, M.J. etc. 2000. Practical Streptomyces Genetics. Norwich, England, The John Innes Foundation.
49. Kim, B. S., T. A. Cropp, B. J. Beck, D. H. Sherman, and K. A. Reynolds. 2002. Biochemical evidence for an editing role of thioesterase II in the biosynthesis of the polyketide pikromycin. J Biol Chem 277:48028-34.
50. Kim, C. Y., V. Y. Alekseyev, A. Y. Chen, Y. Tang, D. E. Cane, and C. Khosla. 2004. Reconstituting modular activity from separated domains of 6-deoxyerythronolide B synthase. Biochemistry 43:13892-8.
51. Kohli, R. M., J. W. Trauger, D. Schwarzer, M. A. Marahiel, and C. T. Walsh. 2001. Generality of peptide cyclization catalyzed by isolated thioesterase domains of nonribosomal peptide synthetases. Biochemistry 40:7099-108.
52. Kotowska, M., K. Pawlik, A. R. Butler, E. Cundliffe, E. Takano, and K. Kuczek. 2002. Type II thioesterase from Streptomyces coelicolor A3(2). Microbiology 148:1777-83.
53. Kreutzenbeck, P., C. Kroger, F. Lausberg, N. Blaudeck, G. A. Sprenger, and R. Freudl. 2007. Escherichia coli twin arginine (Tat) mutant translocases possessing relaxed signal peptide recognition specificities. J Biol Chem 282:7903-11.
54. Lambalot, R. H., A. M. Gehring, R. S. Flugel, P. Zuber, M. LaCelle, M. A. Marahiel, R. Reid, C. Khosla, and C. T. Walsh. 1996. A new enzyme superfamily - the phosphopantetheinyl transferases. Chem Biol 3:923-36.
55. Leblond, P., P. Demuyter, J. M. Simonet, and B. Decaris. 1990. Genetic instability and hypervariability in Streptomyces ambofaciens: towards an understanding of a mechanism of genome plasticity. Mol Microbiol 4:707-14.
56. Linne, U., D. Schwarzer, G. N. Schroeder, and M. A. Marahiel. 2004. Mutational analysis of a type II thioesterase associated with nonribosomal peptide synthesis. Eur J Biochem 271:1536-45.
57. Liu, T., D. You, C. Valenzano, Y. Sun, J. Li, Q. Yu, X. Zhou, D. E. Cane, and Z. Deng. 2006. Identification of NanE as the thioesterase for polyether chain release in nanchangmycin biosynthesis. Chem Biol 13:945-55.
58. Lopez-Errasquin, E., C. Vazquez, M. Jimenez, and M. T. Gonzalez-Jaen. 2007. Real-TimeRT-PCR assay to quantify the expression of fum1 and fum19 genes from the Fumonisin-producing Fusarium verticillioides. J Microbiol Methods 68:312-7.
59. Marsden, A. F., B. Wilkinson, J. Cortes, N. J. Dunster, J. Staunton, and P. F. Leadlay. 1998. Engineering broader specificity into an antibiotic-producing polyketide synthase. Science 279:199-202.
60. McDaniel, R., C. M. Kao, S. J. Hwang, and C. Khosla. 1997. Engineered intermodular and intramodular polyketide synthase fusions. Chem Biol 4:667-74.
61. Mendes, M. V., N. Anton, J. F. Martin, and J. F. Aparicio. 2005. Characterization of the polyene macrolide P450 epoxidase from Streptomyces natalensis that converts de-epoxypimaricin into pimaricin. Biochem J 386:57-62.
62. Mendes, M. V., E. Recio, R. Fouces, R. Luiten, J. F. Martin, and J. F. Aparicio. 2001. Engineered biosynthesis of novel polyenes: a pimaricin derivative produced by targeted gene disruption in Streptomyces natalensis. Chem Biol 8:635-44.
63. Menzella, H. G., R. Reid, J. R. Carney, S. S. Chandran, S. J. Reisinger, K. G. Patel, D. A. Hopwood, and D. V. Santi. 2005. Combinatorial polyketide biosynthesis by de novo design and rearrangement of modular polyketide synthase genes. Nat Biotechnol 23:1171-6.
64. Miller, D. A., L. Luo, N. Hillson, T. A. Keating, and C. T. Walsh. 2002. Yersiniabactin synthetase: a four-protein assembly line producing the nonribosomal peptide/polyketide hybrid siderophore of Yersinia pestis. Chem Biol 9:333-44.
65. Nedal, A., H. Sletta, T. Brautaset, S. E. Borgos, O. N. Sekurova, T. E. Ellingsen, and S. B. Zotchev. 2007. Analysis of the mycosamine biosynthesis and attachment genes in the nystatin biosynthetic gene cluster of Streptomyces noursei ATCC 11455. Appl Environ Microbiol 73:7400-7.
66. Ohnishi, Y., J. Ishikawa, H. Hara, H. Suzuki, M. Ikenoya, H. Ikeda, A. Yamashita, M. Hattori, and S. Horinouchi. 2008. Genome sequence of the streptomycin-producing microorganism Streptomyces griseus IFO 13350. J Bacteriol 190:4050-60.
67. Oliynyk, M., M. Samborskyy, J. B. Lester, T. Mironenko, N. Scott, S. Dickens, S. F. Haydock, and P. F. Leadlay. 2007. Complete genome sequence of the erythromycin-producing bacterium Saccharopolyspora erythraea NRRL23338. Nat Biotechnol 25:447-53.
68. Omura, S. 1992. The expanded horizon for microbial metabolites--a review. Gene 115:141-9.
69. Omura, S., H. Ikeda, J. Ishikawa, A. Hanamoto, C. Takahashi, M. Shinose, Y. Takahashi, H. Horikawa, H. Nakazawa, T. Osonoe, H. Kikuchi, T. Shiba, Y. Sakaki, and M. Hattori. 2001. Genome sequence of an industrial microorganism Streptomyces avermitilis: deducing the ability of producing secondary metabolites. Proc Natl Acad Sci U S A 98:12215-20.
70. Page, N., D. Kluepfel, F. Shareck, and R. Morosoli. 1996. Effect of signal peptide alterations and replacement on export of xylanase A in Streptomyces lividans. Appl Environ Microbiol 62:109-14.
71. Power, P., T. Dunne, B. Murphy, L. N. Lochlainn, D. Rai, C. Borissow, B. Rawlings, and P. Caffrey. 2008. Engineered synthesis of 7-oxo- and 15-deoxy-15-oxo-amphotericins: insights into structure-activity relationships in polyene antibiotics. Chem Biol 15:78-86.
72. Quadri, L. E., P. H. Weinreb, M. Lei, M. M. Nakano, P. Zuber, and C. T. Walsh. 1998. Characterization of Sfp, a Bacillus subtilis phosphopantetheinyl transferase for peptidyl carrier protein domains in peptide synthetases. Biochemistry 37:1585-95.
73. Redenbach, M., H. M. Kieser, D. Denapaite, A. Eichner, J. Cullum, H. Kinashi, and D. A. Hopwood. 1996. A set of ordered cosmids and a detailed genetic and physical map for the 8 Mb Streptomyces coelicolor A3(2) chromosome. Mol Microbiol 21:77-96.
74. Reid, R., M. Piagentini, E. Rodriguez, G. Ashley, N. Viswanathan, J. Carney, D. V. Santi, C. R. Hutchinson, and R. McDaniel. 2003. A model of structure and catalysis for ketoreductase domains in modular polyketide synthases. Biochemistry 42:72-9.
75. Rigali, S., H. Nothaft, E. E. Noens, M. Schlicht, S. Colson, M. Muller, B. Joris, H. K. Koerten, D. A. Hopwood, F. Titgemeyer, and G. P. van Wezel. 2006. The sugar phosphotransferase system of Streptomyces coelicolor is regulated by the GntR-family regulator DasR and links N-acetylglucosamine metabolism to the control of development. Mol Microbiol 61:1237-51.
76. Sambrook, J., Fritsch, E.F., and Maniatis, T. . 1989. Molecular Cloning: A Laboratory Manual, Second Edition. New York, Cold Spring Harbor Laboratory Press.
77. Schaerlaekens, K., E. Lammertyn, N. Geukens, S. De Keersmaeker, J. Anne, and L. Van Mellaert. 2004. Comparison of the Sec and Tat secretion pathways for heterologous protein production by Streptomyces lividans. J Biotechnol 112:279-88.
78. Schaerlaekens, K., M. Schierova, E. Lammertyn, N. Geukens, J. Anne, and L. Van Mellaert. 2001. Twin-arginine translocation pathway in Streptomyces lividans. J Bacteriol 183:6727-32.
79. Schnarr, N. A., and C. Khosla. 2006. Trapping transient protein-protein interactions in polyketide biosynthesis. ACS Chem Biol 1:679-80.
80. Schneider, A., and M. A. Marahiel. 1998. Genetic evidence for a role of thioesterase domains, integrated in or associated with peptide synthetases, in non-ribosomal peptide biosynthesis in Bacillus subtilis. Arch Microbiol 169:404-10.
81. Schwarzer, D., H. D. Mootz, U. Linne, and M. A. Marahiel. 2002. Regeneration of misprimed nonribosomal peptide synthetases by type II thioesterases. Proc Natl Acad Sci U S A 99:14083-8.
82. Schwarzer, D., H. D. Mootz, and M. A. Marahiel. 2001. Exploring the impact of different thioesterase domains for the design of hybrid peptide synthetases. Chem Biol 8:997-1010.
83. Schwecke, T., J. F. Aparicio, I. Molnar, A. Konig, L. E. Khaw, S. F. Haydock, M. Oliynyk, P. Caffrey, J. Cortes, J. B. Lester, and et al. 1995. The biosynthetic gene cluster for the polyketide immunosuppressant rapamycin. Proc Natl Acad Sci U S A 92:7839-43.
84. Sekurova, O. N., T. Brautaset, H. Sletta, S. E. Borgos, M. O. Jakobsen, T. E. Ellingsen, A. R. Strom, S. Valla, and S. B. Zotchev. 2004. In vivo analysis of the regulatory genes in the nystatin biosynthetic gene cluster of Streptomyces noursei ATCC 11455 reveals their differential control over antibiotic biosynthesis. J Bacteriol 186:1345-54.
85. Sharma, K. K., and C. N. Boddy. 2007. The thioesterase domain from the pimaricin and erythromycin biosynthetic pathways can catalyze hydrolysis of simple thioester substrates. Bioorg Med Chem Lett 17:3034-7.
86. Short, J. M., J. M. Fernandez, J. A. Sorge, and W. D. Huse. 1988. Lambda ZAP: a bacteriophage lambda expression vector with in vivo excision properties. Nucleic Acids Res 16:7583-600.
87. Sletta, H., S. E. Borgos, P. Bruheim, O. N. Sekurova, H. Grasdalen, R. Aune, T. E. Ellingsen, and S. B. Zotchev. 2005. Nystatin biosynthesis and transport: nysH and nysGgenes encoding a putative ABC transporter system in Streptomyces noursei ATCC 11455 are required for efficient conversion of 10-deoxynystatin to nystatin. Antimicrob Agents Chemother 49:4576-83.
88. Smith, S. 1994. The animal fatty acid synthase: one gene, one polypeptide, seven enzymes. Faseb J 8:1248-59.
89. Stassi, D., D. Post, M. Satter, M. Jackson, and G. Maine. 1998. A genetically engineered strain of Saccharopolyspora erythraea that produces 6,12-dideoxyerythromycin A as the major fermentation product. Appl Microbiol Biotechnol 49:725-31.
90. Stutzman-Engwall, K., S. Conlon, R. Fedechko, H. McArthur, K. Pekrun, Y. Chen, S. Jenne, C. La, N. Trinh, S. Kim, Y. X. Zhang, R. Fox, C. Gustafsson, and A. Krebber. 2005. Semi-synthetic DNA shuffling of aveC leads to improved industrial scale production of doramectin by Streptomyces avermitilis. Metab Eng 7:27-37.
91. Sun, Y., X. Zhou, H. Dong, G. Tu, M. Wang, B. Wang, and Z. Deng. 2003. A complete gene cluster from Streptomyces nanchangensis NS3226 encoding biosynthesis of the polyether ionophore nanchangmycin. Chem Biol 10:431-41.
92. Sun, Y., X. Zhou, J. Liu, K. Bao, G. Zhang, G. Tu, T. Kieser, and Z. Deng. 2002. 'Streptomyces nanchangensis', a producer of the insecticidal polyether antibiotic nanchangmycin and the antiparasitic macrolide meilingmycin, contains multiple polyketide gene clusters. Microbiology 148:361-71.
93. Tai, M. H., S. S. Chirala, and S. J. Wakil. 1993. Roles of Ser101, Asp236, and His237 in catalysis of thioesterase II and of the C-terminal region of the enzyme in its interaction with fatty acid synthase. Proc Natl Acad Sci U S A 90:1852-6.
94. Tang, L., H. Fu, M. C. Betlach, and R. McDaniel. 1999. Elucidating the mechanism of chain termination switching in the picromycin/methymycin polyketide synthase. Chem Biol 6:553-8.
95. Tang, L., S. Shah, L. Chung, J. Carney, L. Katz, C. Khosla, and B. Julien. 2000. Cloning and heterologous expression of the epothilone gene cluster. Science 287:640-2.
96. Tang, L., Y. J. Yoon, C. Y. Choi, and C. R. Hutchinson. 1998. Characterization of the enzymatic domains in the modular polyketide synthase involved in rifamycin B biosynthesis by Amycolatopsis mediterranei. Gene 216:255-65.
97. Taylor, B. L., and I. B. Zhulin. 1999. PAS domains: internal sensors of oxygen, redox potential, and light. Microbiol Mol Biol Rev 63:479-506.
98. Thomas, J., and J. E. Cronan. 2005. The enigmatic acyl carrier protein phosphodiesterase of Escherichia coli: genetic and enzymological characterization. J Biol Chem 280:34675-83.
99. Traag, B. A., and G. P. van Wezel. 2008. The SsgA-like proteins in actinomycetes: small proteins up to a big task. Antonie Van Leeuwenhoek 94:85-97.
100. Van Lanen, S. G., and B. Shen. 2008. Advances in polyketide synthase structure and function. Curr Opin Drug Discov Devel 11:186-95.
101. Volokhan, O., H. Sletta, T. E. Ellingsen, and S. B. Zotchev. 2006. Characterization of the P450 monooxygenase NysL, responsible for C-10 hydroxylation during biosynthesis of the polyene macrolide antibiotic nystatin in Streptomyces noursei. Appl Environ Microbiol 72:2514-9.
102. Wakesman, S. A., Heriai, A.T. . 1943. The nomenclature and classification of the Actinomyces. J Bacteriol 46:337-341.
103. Walsh, C. T. 2005. Natural insights for chemical biologists. Nat Chem Biol 1:122-4.
104. Wilkinson, C. J., Z. A. Hughes-Thomas, C. J. Martin, I. Bohm, T. Mironenko, M. Deacon, M. Wheatcroft, G. Wirtz, J. Staunton, and P. F. Leadlay. 2002. Increasing the efficiency of heterologous promoters in actinomycetes. J Mol Microbiol Biotechnol 4:417-26.
105. Wilson, D. J., Y. Xue, K. A. Reynolds, and D. H. Sherman. 2001. Characterization and analysis of the PikD regulatory factor in the pikromycin biosynthetic pathway of Streptomyces venezuelae. J Bacteriol 183:3468-75.
106. Yeh, E., R. M. Kohli, S. D. Bruner, and C. T. Walsh. 2004. Type II thioesterase restores activity of a NRPS module stalled with an aminoacyl-S-enzyme that cannot be elongated. Chembiochem 5:1290-3.
107. Yongjun Zhou, Q. M., Delin You, Jialiang Li, Shi Chen, Dazhong Ding, Xiufen Zhou, Huchen Zhou, Linquan Bai, and Zixin Deng. 2008. Selective removal of the aberrant extender units by a type II thioesterase for the efficient FR-008/candicidin biosynthesis in Streptomyces sp. FR-008. Appl Environ Microbiol.
108. Zhao, C., J. Ju, S. D. Christenson, W. C. Smith, D. Song, X. Zhou, B. Shen, and Z. Deng. 2006. Utilization of the methoxymalonyl-acyl carrier protein biosynthesis locus for cloning the oxazolomycin biosynthetic gene cluster from Streptomyces albus JA3453. J Bacteriol 188:4142-7.
109. Zhou, Y., J. Li, J. Zhu, S. Chen, L. Bai, X. Zhou, H. Wu, and Z. Deng. 2008. Incomplete beta-ketone processing as a mechanism for polyene structural variation in the FR-008/candicidin complex. Chem Biol 15:629-38.
110. Zielinski J, B.-B. H., Golik J, Gumieniak J, Ziminski T,, and P. J. Kolodzi-Ejczyk P, Borwoski E. 1979. The structure of levorin A2 and candicidin D. Tetrahedron Lett 20:1791–1794.
111. Zotchev, S. B. 2003. Polyene macrolide antibiotics and their applications in human therapy. Curr Med Chem 10:211-23.
2. Anton, N., M. V. Mendes, J. F. Martin, and J. F. Aparicio. 2004. Identification of PimR as a positive regulator of pimaricin biosynthesis in Streptomyces natalensis. J Bacteriol 186:2567-75.
3. Aparicio, J. F., P. Caffrey, J. A. Gil, and S. B. Zotchev. 2003. Polyene antibiotic biosynthesis gene clusters. Appl Microbiol Biotechnol 61:179-88.
4. Aparicio, J. F., R. Fouces, M. V. Mendes, N. Olivera, and J. F. Martin. 2000. A complex multienzyme system encoded by five polyketide synthase genes is involved in the biosynthesis of the 26-membered polyene macrolide pimaricin in Streptomyces natalensis. Chem Biol 7:895-905.
5. Aparicio, J. F., M. V. Mendes, N. Anton, E. Recio, and J. F. Martin. 2004. Polyene macrolide antibiotic biosynthesis. Curr Med Chem 11:1645-56.
6. Bentley, S. D., S. Brown, L. D. Murphy, D. E. Harris, M. A. Quail, J. Parkhill, B. G. Barrell, J. R. McCormick, R. I. Santamaria, R. Losick, M. Yamasaki, H. Kinashi, C. W. Chen, G. Chandra, D. Jakimowicz, H. M. Kieser, T. Kieser, and K. F. Chater. 2004. SCP1, a 356,023 bp linear plasmid adapted to the ecology and developmental biology of its host, Streptomyces coelicolor A3(2). Mol Microbiol 51:1615-28.
7. Bentley, S. D., K. F. Chater, A. M. Cerdeno-Tarraga, G. L. Challis, N. R. Thomson, K. D. James, D. E. Harris, M. A. Quail, H. Kieser, D. Harper, A. Bateman, S. Brown, G. Chandra, C. W. Chen, M. Collins, A. Cronin, A. Fraser, A. Goble, J. Hidalgo, T. Hornsby, S. Howarth, C. H. Huang, T. Kieser, L. Larke, L. Murphy, K. Oliver, S. O'Neil, E. Rabbinowitsch, M. A. Rajandream, K. Rutherford, S. Rutter, K. Seeger, D. Saunders, S. Sharp, R. Squares, S. Squares, K. Taylor, T. Warren, A. Wietzorrek, J. Woodward, B. G. Barrell, J. Parkhill, and D. A. Hopwood. 2002. Complete genome sequence of the model actinomycete Streptomyces coelicolor A3(2). Nature 417:141-7.
8. Birch, A., A. Hausler, and R. Hutter. 1990. Genome rearrangement and genetic instability in Streptomyces spp. J Bacteriol 172:4138-42.
9. Blatch, G. L., and M. Lassle. 1999. The tetratricopeptide repeat: a structural motif mediating protein-protein interactions. Bioessays 21:932-9.
10. Borgos, S. E., H. Sletta, E. Fjaervik, T. Brautaset, T. E. Ellingsen, O. M. Gulliksen, and S. B. Zotchev. 2006. Effect of glucose limitation and specific mutations in the module 5 enoyl reductase domains in the nystatin and amphotericin polyketide synthases on polyene macrolide biosynthesis. Arch Microbiol 185:165-71.
11. Borgos, S. E., P. Tsan, H. Sletta, T. E. Ellingsen, J. M. Lancelin, and S. B. Zotchev. 2006. Probing the structure-function relationship of polyene macrolides: engineered biosynthesis of soluble nystatin analogues. J Med Chem 49:2431-9.
12. Brautaset, T., S. E. Borgos, H. Sletta, T. E. Ellingsen, and S. B. Zotchev. 2003.Site-specific mutagenesis and domain substitutions in the loading module of the nystatin polyketide synthase, and their effects on nystatin biosynthesis in Streptomyces noursei. J Biol Chem 278:14913-9.
13. Brautaset, T., O. N. Sekurova, H. Sletta, T. E. Ellingsen, A. R. StrLm, S. Valla, and S. B. Zotchev. 2000. Biosynthesis of the polyene antifungal antibiotic nystatin in Streptomyces noursei ATCC 11455: analysis of the gene cluster and deduction of the biosynthetic pathway. Chem Biol 7:395-403.
14. Brodhagen, M., I. Paulsen, and J. E. Loper. 2005. Reciprocal regulation of pyoluteorin production with membrane transporter gene expression in Pseudomonas fluorescens Pf-5. Appl Environ Microbiol 71:6900-9.
15. Bruheim, P., S. E. Borgos, P. Tsan, H. Sletta, T. E. Ellingsen, J. M. Lancelin, and S. B. Zotchev. 2004. Chemical diversity of polyene macrolides produced by Streptomyces noursei ATCC 11455 and recombinant strain ERD44 with genetically altered polyketide synthase NysC. Antimicrob Agents Chemother 48:4120-9.
16. Butler, A. R., N. Bate, and E. Cundliffe. 1999. Impact of thioesterase activity on tylosin biosynthesis in Streptomyces fradiae. Chem Biol 6:287-92.
17. Byrne, B., M. Carmody, E. Gibson, B. Rawlings, and P. Caffrey. 2003. Biosynthesis of deoxyamphotericins and deoxyamphoteronolides by engineered strains of Streptomyces nodosus. Chem Biol 10:1215-24.
18. Caffrey, P., J. F. Aparicio, F. Malpartida, and S. B. Zotchev. 2008. Biosynthetic engineering of polyene macrolides towards generation of improved antifungal and antiparasitic agents. Curr Top Med Chem 8:639-53.
19. Caffrey, P., S. Lynch, E. Flood, S. Finnan, and M. Oliynyk. 2001. Amphotericin biosynthesis in Streptomyces nodosus: deductions from analysis of polyketide synthase and late genes. Chem Biol 8:713-23.
20. Campelo, A. B., and J. A. Gil. 2002. The candicidin gene cluster from Streptomyces griseus IMRU 3570. Microbiology 148:51-9.
21. Carmody, M., B. Murphy, B. Byrne, P. Power, D. Rai, B. Rawlings, and P. Caffrey. 2005. Biosynthesis of amphotericin derivatives lacking exocyclic carboxyl groups. J Biol Chem 280:34420-6.
22. Chalut, C., L. Botella, C. de Sousa-D'Auria, C. Houssin, and C. Guilhot. 2006. The nonredundant roles of two 4'-phosphopantetheinyl transferases in vital processes of Mycobacteria. Proc Natl Acad Sci U S A 103:8511-6.
23. Chater, K. F. 1992. Genetic regulation of secondary metabolic pathways in Streptomyces. Ciba Found Symp 171:144-56; discussion 156-62.
24. Chen, S., X. Huang, X. Zhou, L. Bai, J. He, K. J. Jeong, S. Y. Lee, and Z. Deng. 2003. Organizational and mutational analysis of a complete FR-008/candicidin gene cluster encoding a structurally related polyene complex. Chem Biol 10:1065-76.
25. Chen, S., J. B. Roberts, Y. Xue, D. H. Sherman, and K. A. Reynolds. 2001. The Streptomyces venezuelae pikAV gene contains a transcription unit essential for expression of enzymes involved in glycosylation of narbonolide and 10-deoxymethynolide. Gene 263:255-64.
26. Cundliffe, E., N. Bate, A. Butler, S. Fish, A. Gandecha, and L. Merson-Davies. 2001. The tylosin-biosynthetic genes of Streptomyces fradiae. Antonie Van Leeuwenhoek 79:229-34.
27. Del Vecchio, F., H. Petkovic, S. G. Kendrew, L. Low, B. Wilkinson, R. Lill, J. Cortes, B. A. Rudd, J. Staunton, and P. F. Leadlay. 2003. Active-site residue, domain and module swaps in modular polyketide synthases. J Ind Microbiol Biotechnol 30:489-94.
28. Doi-Katayama, Y., Y. J. Yoon, C. Y. Choi, T. W. Yu, H. G. Floss, and C. R. Hutchinson. 2000. Thioesterases and the premature termination of polyketide chain elongation in rifamycin B biosynthesis by Amycolatopsis mediterranei S699. J Antibiot (Tokyo) 53:484-95.
29. Enquist M, B. 1971. Characterization of deoxyribonucleic acid from Streptomyces venezulae spores. Dev Ind Microbiol 12:225-236.
30. Fischbach, M. A., and C. T. Walsh. 2006. Assembly-line enzymology for polyketide and nonribosomal Peptide antibiotics: logic, machinery, and mechanisms. Chem Rev 106:3468-96.
31. Fischl, A. S., and E. P. Kennedy. 1990. Isolation and properties of acyl carrier protein phosphodiesterase of Escherichia coli. J Bacteriol 172:5445-9.
32. Geoffroy, V. A., J. D. Fetherston, and R. D. Perry. 2000. Yersinia pestis YbtU and YbtT are involved in synthesis of the siderophore yersiniabactin but have different effects on regulation. Infect Immun 68:4452-61.
33. Gokhale, R. S., D. Hunziker, D. E. Cane, and C. Khosla. 1999. Mechanism and specificity of the terminal thioesterase domain from the erythromycin polyketide synthase. Chem Biol 6:117-25.
34. Guimond, J., and R. Morosoli. 2008. Identification of Streptomyces lividans proteins secreted by the twin-arginine translocation pathway following growth with different carbon sources. Can J Microbiol 54:549-58.
35. Harvey, B. M., H. Hong, M. A. Jones, Z. A. Hughes-Thomas, R. M. Goss, M. L. Heathcote, V. M. Bolanos-Garcia, W. Kroutil, J. Staunton, P. F. Leadlay, and J. B. Spencer. 2006. Evidence that a novel thioesterase is responsible for polyketide chain release during biosynthesis of the polyether ionophore monensin. Chembiochem 7:1435-42.
36. Heathcote, M. L., J. Staunton, and P. F. Leadlay. 2001. Role of type II thioesterases: evidence for removal of short acyl chains produced by aberrant decarboxylation of chain extender units. Chem Biol 8:207-20.
37. Hopwood, D. A. 1999. Forty years of genetics with Streptomyces: from in vivo through in vitro to in silico. Microbiology 145 ( Pt 9):2183-202.
38. Hopwood, D. A. 1997. Genetic Contributions to Understanding Polyketide Synthases. Chem Rev 97:2465-2498.
39. Hopwood, D. A., M. J. Bibb, K. F. Chater, T. Kieser, C. J. Bruton, H. M. Kieser, D. J. Lydiate, C. P. Smith, J. M. Ward, and H. Schrempf. 1985. Genetic Manipulation of Streptomyces-A Laboratory Manual. The John Innes Foundation, Norwich.
40. Hu, Z., K. Bao, X. Zhou, Q. Zhou, D. A. Hopwood, T. Kieser, and Z. Deng. 1994. Repeated polyketide synthase modules involved in the biosynthesis of a heptaene macrolide by Streptomyces sp. FR-008. Mol Microbiol 14:163-72.
41. Hu, Z., B. A. Pfeifer, E. Chao, S. Murli, J. Kealey, J. R. Carney, G. Ashley, C. Khosla, and C. R. Hutchinson. 2003. A specific role of the Saccharopolyspora erythraea thioesterase II gene in the function of modular polyketide synthases. Microbiology 149:2213-25.
42. Huang, Y., E. Wendt-Pienkowski, and B. Shen. 2006. A dedicated phosphopantetheinyl transferase for the fredericamycin polyketide synthase from Streptomyces griseus. J Biol Chem 281:29660-8.
43. Ikeda, H., T. Nonomiya, and S. Omura. 2001. Organization of biosynthetic gene cluster for avermectin in Streptomyces avermitilis: analysis of enzymatic domains in four polyketide synthases. J Ind Microbiol Biotechnol 27:170-6.
44. Ikeda, H., T. Nonomiya, M. Usami, T. Ohta, and S. Omura. 1999. Organization of the biosynthetic gene cluster for the polyketide anthelmintic macrolide avermectin in Streptomyces avermitilis. Proc Natl Acad Sci U S A 96:9509-14.
45. Janssen, G. R., and M. J. Bibb. 1993. Derivatives of pUC18 that have BglII sites flanking a modified multiple cloning site and that retain the ability to identify recombinant clones by visual screening of Escherichia coli colonies. Gene 124:133-134.
46. Jung, W. S., S. K. Lee, J. S. Hong, S. R. Park, S. J. Jeong, A. R. Han, J. K. Sohng, B. G. Kim, C. Y. Choi, D. H. Sherman, and Y. J. Yoon. 2006. Heterologous expression of tylosin polyketide synthase and production of a hybrid bioactive macrolide in Streptomyces venezuelae. Appl Microbiol Biotechnol 72:763-9.
47. Khosla, C., Y. Tang, A. Y. Chen, N. A. Schnarr, and D. E. Cane. 2007. Structure and mechanism of the 6-deoxyerythronolide B synthase. Annu Rev Biochem 76:195-221.
48. Kieser, T., Bibb, M.J., Buttner, M.J. etc. 2000. Practical Streptomyces Genetics. Norwich, England, The John Innes Foundation.
49. Kim, B. S., T. A. Cropp, B. J. Beck, D. H. Sherman, and K. A. Reynolds. 2002. Biochemical evidence for an editing role of thioesterase II in the biosynthesis of the polyketide pikromycin. J Biol Chem 277:48028-34.
50. Kim, C. Y., V. Y. Alekseyev, A. Y. Chen, Y. Tang, D. E. Cane, and C. Khosla. 2004. Reconstituting modular activity from separated domains of 6-deoxyerythronolide B synthase. Biochemistry 43:13892-8.
51. Kohli, R. M., J. W. Trauger, D. Schwarzer, M. A. Marahiel, and C. T. Walsh. 2001. Generality of peptide cyclization catalyzed by isolated thioesterase domains of nonribosomal peptide synthetases. Biochemistry 40:7099-108.
52. Kotowska, M., K. Pawlik, A. R. Butler, E. Cundliffe, E. Takano, and K. Kuczek. 2002. Type II thioesterase from Streptomyces coelicolor A3(2). Microbiology 148:1777-83.
53. Kreutzenbeck, P., C. Kroger, F. Lausberg, N. Blaudeck, G. A. Sprenger, and R. Freudl. 2007. Escherichia coli twin arginine (Tat) mutant translocases possessing relaxed signal peptide recognition specificities. J Biol Chem 282:7903-11.
54. Lambalot, R. H., A. M. Gehring, R. S. Flugel, P. Zuber, M. LaCelle, M. A. Marahiel, R. Reid, C. Khosla, and C. T. Walsh. 1996. A new enzyme superfamily - the phosphopantetheinyl transferases. Chem Biol 3:923-36.
55. Leblond, P., P. Demuyter, J. M. Simonet, and B. Decaris. 1990. Genetic instability and hypervariability in Streptomyces ambofaciens: towards an understanding of a mechanism of genome plasticity. Mol Microbiol 4:707-14.
56. Linne, U., D. Schwarzer, G. N. Schroeder, and M. A. Marahiel. 2004. Mutational analysis of a type II thioesterase associated with nonribosomal peptide synthesis. Eur J Biochem 271:1536-45.
57. Liu, T., D. You, C. Valenzano, Y. Sun, J. Li, Q. Yu, X. Zhou, D. E. Cane, and Z. Deng. 2006. Identification of NanE as the thioesterase for polyether chain release in nanchangmycin biosynthesis. Chem Biol 13:945-55.
58. Lopez-Errasquin, E., C. Vazquez, M. Jimenez, and M. T. Gonzalez-Jaen. 2007. Real-TimeRT-PCR assay to quantify the expression of fum1 and fum19 genes from the Fumonisin-producing Fusarium verticillioides. J Microbiol Methods 68:312-7.
59. Marsden, A. F., B. Wilkinson, J. Cortes, N. J. Dunster, J. Staunton, and P. F. Leadlay. 1998. Engineering broader specificity into an antibiotic-producing polyketide synthase. Science 279:199-202.
60. McDaniel, R., C. M. Kao, S. J. Hwang, and C. Khosla. 1997. Engineered intermodular and intramodular polyketide synthase fusions. Chem Biol 4:667-74.
61. Mendes, M. V., N. Anton, J. F. Martin, and J. F. Aparicio. 2005. Characterization of the polyene macrolide P450 epoxidase from Streptomyces natalensis that converts de-epoxypimaricin into pimaricin. Biochem J 386:57-62.
62. Mendes, M. V., E. Recio, R. Fouces, R. Luiten, J. F. Martin, and J. F. Aparicio. 2001. Engineered biosynthesis of novel polyenes: a pimaricin derivative produced by targeted gene disruption in Streptomyces natalensis. Chem Biol 8:635-44.
63. Menzella, H. G., R. Reid, J. R. Carney, S. S. Chandran, S. J. Reisinger, K. G. Patel, D. A. Hopwood, and D. V. Santi. 2005. Combinatorial polyketide biosynthesis by de novo design and rearrangement of modular polyketide synthase genes. Nat Biotechnol 23:1171-6.
64. Miller, D. A., L. Luo, N. Hillson, T. A. Keating, and C. T. Walsh. 2002. Yersiniabactin synthetase: a four-protein assembly line producing the nonribosomal peptide/polyketide hybrid siderophore of Yersinia pestis. Chem Biol 9:333-44.
65. Nedal, A., H. Sletta, T. Brautaset, S. E. Borgos, O. N. Sekurova, T. E. Ellingsen, and S. B. Zotchev. 2007. Analysis of the mycosamine biosynthesis and attachment genes in the nystatin biosynthetic gene cluster of Streptomyces noursei ATCC 11455. Appl Environ Microbiol 73:7400-7.
66. Ohnishi, Y., J. Ishikawa, H. Hara, H. Suzuki, M. Ikenoya, H. Ikeda, A. Yamashita, M. Hattori, and S. Horinouchi. 2008. Genome sequence of the streptomycin-producing microorganism Streptomyces griseus IFO 13350. J Bacteriol 190:4050-60.
67. Oliynyk, M., M. Samborskyy, J. B. Lester, T. Mironenko, N. Scott, S. Dickens, S. F. Haydock, and P. F. Leadlay. 2007. Complete genome sequence of the erythromycin-producing bacterium Saccharopolyspora erythraea NRRL23338. Nat Biotechnol 25:447-53.
68. Omura, S. 1992. The expanded horizon for microbial metabolites--a review. Gene 115:141-9.
69. Omura, S., H. Ikeda, J. Ishikawa, A. Hanamoto, C. Takahashi, M. Shinose, Y. Takahashi, H. Horikawa, H. Nakazawa, T. Osonoe, H. Kikuchi, T. Shiba, Y. Sakaki, and M. Hattori. 2001. Genome sequence of an industrial microorganism Streptomyces avermitilis: deducing the ability of producing secondary metabolites. Proc Natl Acad Sci U S A 98:12215-20.
70. Page, N., D. Kluepfel, F. Shareck, and R. Morosoli. 1996. Effect of signal peptide alterations and replacement on export of xylanase A in Streptomyces lividans. Appl Environ Microbiol 62:109-14.
71. Power, P., T. Dunne, B. Murphy, L. N. Lochlainn, D. Rai, C. Borissow, B. Rawlings, and P. Caffrey. 2008. Engineered synthesis of 7-oxo- and 15-deoxy-15-oxo-amphotericins: insights into structure-activity relationships in polyene antibiotics. Chem Biol 15:78-86.
72. Quadri, L. E., P. H. Weinreb, M. Lei, M. M. Nakano, P. Zuber, and C. T. Walsh. 1998. Characterization of Sfp, a Bacillus subtilis phosphopantetheinyl transferase for peptidyl carrier protein domains in peptide synthetases. Biochemistry 37:1585-95.
73. Redenbach, M., H. M. Kieser, D. Denapaite, A. Eichner, J. Cullum, H. Kinashi, and D. A. Hopwood. 1996. A set of ordered cosmids and a detailed genetic and physical map for the 8 Mb Streptomyces coelicolor A3(2) chromosome. Mol Microbiol 21:77-96.
74. Reid, R., M. Piagentini, E. Rodriguez, G. Ashley, N. Viswanathan, J. Carney, D. V. Santi, C. R. Hutchinson, and R. McDaniel. 2003. A model of structure and catalysis for ketoreductase domains in modular polyketide synthases. Biochemistry 42:72-9.
75. Rigali, S., H. Nothaft, E. E. Noens, M. Schlicht, S. Colson, M. Muller, B. Joris, H. K. Koerten, D. A. Hopwood, F. Titgemeyer, and G. P. van Wezel. 2006. The sugar phosphotransferase system of Streptomyces coelicolor is regulated by the GntR-family regulator DasR and links N-acetylglucosamine metabolism to the control of development. Mol Microbiol 61:1237-51.
76. Sambrook, J., Fritsch, E.F., and Maniatis, T. . 1989. Molecular Cloning: A Laboratory Manual, Second Edition. New York, Cold Spring Harbor Laboratory Press.
77. Schaerlaekens, K., E. Lammertyn, N. Geukens, S. De Keersmaeker, J. Anne, and L. Van Mellaert. 2004. Comparison of the Sec and Tat secretion pathways for heterologous protein production by Streptomyces lividans. J Biotechnol 112:279-88.
78. Schaerlaekens, K., M. Schierova, E. Lammertyn, N. Geukens, J. Anne, and L. Van Mellaert. 2001. Twin-arginine translocation pathway in Streptomyces lividans. J Bacteriol 183:6727-32.
79. Schnarr, N. A., and C. Khosla. 2006. Trapping transient protein-protein interactions in polyketide biosynthesis. ACS Chem Biol 1:679-80.
80. Schneider, A., and M. A. Marahiel. 1998. Genetic evidence for a role of thioesterase domains, integrated in or associated with peptide synthetases, in non-ribosomal peptide biosynthesis in Bacillus subtilis. Arch Microbiol 169:404-10.
81. Schwarzer, D., H. D. Mootz, U. Linne, and M. A. Marahiel. 2002. Regeneration of misprimed nonribosomal peptide synthetases by type II thioesterases. Proc Natl Acad Sci U S A 99:14083-8.
82. Schwarzer, D., H. D. Mootz, and M. A. Marahiel. 2001. Exploring the impact of different thioesterase domains for the design of hybrid peptide synthetases. Chem Biol 8:997-1010.
83. Schwecke, T., J. F. Aparicio, I. Molnar, A. Konig, L. E. Khaw, S. F. Haydock, M. Oliynyk, P. Caffrey, J. Cortes, J. B. Lester, and et al. 1995. The biosynthetic gene cluster for the polyketide immunosuppressant rapamycin. Proc Natl Acad Sci U S A 92:7839-43.
84. Sekurova, O. N., T. Brautaset, H. Sletta, S. E. Borgos, M. O. Jakobsen, T. E. Ellingsen, A. R. Strom, S. Valla, and S. B. Zotchev. 2004. In vivo analysis of the regulatory genes in the nystatin biosynthetic gene cluster of Streptomyces noursei ATCC 11455 reveals their differential control over antibiotic biosynthesis. J Bacteriol 186:1345-54.
85. Sharma, K. K., and C. N. Boddy. 2007. The thioesterase domain from the pimaricin and erythromycin biosynthetic pathways can catalyze hydrolysis of simple thioester substrates. Bioorg Med Chem Lett 17:3034-7.
86. Short, J. M., J. M. Fernandez, J. A. Sorge, and W. D. Huse. 1988. Lambda ZAP: a bacteriophage lambda expression vector with in vivo excision properties. Nucleic Acids Res 16:7583-600.
87. Sletta, H., S. E. Borgos, P. Bruheim, O. N. Sekurova, H. Grasdalen, R. Aune, T. E. Ellingsen, and S. B. Zotchev. 2005. Nystatin biosynthesis and transport: nysH and nysGgenes encoding a putative ABC transporter system in Streptomyces noursei ATCC 11455 are required for efficient conversion of 10-deoxynystatin to nystatin. Antimicrob Agents Chemother 49:4576-83.
88. Smith, S. 1994. The animal fatty acid synthase: one gene, one polypeptide, seven enzymes. Faseb J 8:1248-59.
89. Stassi, D., D. Post, M. Satter, M. Jackson, and G. Maine. 1998. A genetically engineered strain of Saccharopolyspora erythraea that produces 6,12-dideoxyerythromycin A as the major fermentation product. Appl Microbiol Biotechnol 49:725-31.
90. Stutzman-Engwall, K., S. Conlon, R. Fedechko, H. McArthur, K. Pekrun, Y. Chen, S. Jenne, C. La, N. Trinh, S. Kim, Y. X. Zhang, R. Fox, C. Gustafsson, and A. Krebber. 2005. Semi-synthetic DNA shuffling of aveC leads to improved industrial scale production of doramectin by Streptomyces avermitilis. Metab Eng 7:27-37.
91. Sun, Y., X. Zhou, H. Dong, G. Tu, M. Wang, B. Wang, and Z. Deng. 2003. A complete gene cluster from Streptomyces nanchangensis NS3226 encoding biosynthesis of the polyether ionophore nanchangmycin. Chem Biol 10:431-41.
92. Sun, Y., X. Zhou, J. Liu, K. Bao, G. Zhang, G. Tu, T. Kieser, and Z. Deng. 2002. 'Streptomyces nanchangensis', a producer of the insecticidal polyether antibiotic nanchangmycin and the antiparasitic macrolide meilingmycin, contains multiple polyketide gene clusters. Microbiology 148:361-71.
93. Tai, M. H., S. S. Chirala, and S. J. Wakil. 1993. Roles of Ser101, Asp236, and His237 in catalysis of thioesterase II and of the C-terminal region of the enzyme in its interaction with fatty acid synthase. Proc Natl Acad Sci U S A 90:1852-6.
94. Tang, L., H. Fu, M. C. Betlach, and R. McDaniel. 1999. Elucidating the mechanism of chain termination switching in the picromycin/methymycin polyketide synthase. Chem Biol 6:553-8.
95. Tang, L., S. Shah, L. Chung, J. Carney, L. Katz, C. Khosla, and B. Julien. 2000. Cloning and heterologous expression of the epothilone gene cluster. Science 287:640-2.
96. Tang, L., Y. J. Yoon, C. Y. Choi, and C. R. Hutchinson. 1998. Characterization of the enzymatic domains in the modular polyketide synthase involved in rifamycin B biosynthesis by Amycolatopsis mediterranei. Gene 216:255-65.
97. Taylor, B. L., and I. B. Zhulin. 1999. PAS domains: internal sensors of oxygen, redox potential, and light. Microbiol Mol Biol Rev 63:479-506.
98. Thomas, J., and J. E. Cronan. 2005. The enigmatic acyl carrier protein phosphodiesterase of Escherichia coli: genetic and enzymological characterization. J Biol Chem 280:34675-83.
99. Traag, B. A., and G. P. van Wezel. 2008. The SsgA-like proteins in actinomycetes: small proteins up to a big task. Antonie Van Leeuwenhoek 94:85-97.
100. Van Lanen, S. G., and B. Shen. 2008. Advances in polyketide synthase structure and function. Curr Opin Drug Discov Devel 11:186-95.
101. Volokhan, O., H. Sletta, T. E. Ellingsen, and S. B. Zotchev. 2006. Characterization of the P450 monooxygenase NysL, responsible for C-10 hydroxylation during biosynthesis of the polyene macrolide antibiotic nystatin in Streptomyces noursei. Appl Environ Microbiol 72:2514-9.
102. Wakesman, S. A., Heriai, A.T. . 1943. The nomenclature and classification of the Actinomyces. J Bacteriol 46:337-341.
103. Walsh, C. T. 2005. Natural insights for chemical biologists. Nat Chem Biol 1:122-4.
104. Wilkinson, C. J., Z. A. Hughes-Thomas, C. J. Martin, I. Bohm, T. Mironenko, M. Deacon, M. Wheatcroft, G. Wirtz, J. Staunton, and P. F. Leadlay. 2002. Increasing the efficiency of heterologous promoters in actinomycetes. J Mol Microbiol Biotechnol 4:417-26.
105. Wilson, D. J., Y. Xue, K. A. Reynolds, and D. H. Sherman. 2001. Characterization and analysis of the PikD regulatory factor in the pikromycin biosynthetic pathway of Streptomyces venezuelae. J Bacteriol 183:3468-75.
106. Yeh, E., R. M. Kohli, S. D. Bruner, and C. T. Walsh. 2004. Type II thioesterase restores activity of a NRPS module stalled with an aminoacyl-S-enzyme that cannot be elongated. Chembiochem 5:1290-3.
107. Yongjun Zhou, Q. M., Delin You, Jialiang Li, Shi Chen, Dazhong Ding, Xiufen Zhou, Huchen Zhou, Linquan Bai, and Zixin Deng. 2008. Selective removal of the aberrant extender units by a type II thioesterase for the efficient FR-008/candicidin biosynthesis in Streptomyces sp. FR-008. Appl Environ Microbiol.
108. Zhao, C., J. Ju, S. D. Christenson, W. C. Smith, D. Song, X. Zhou, B. Shen, and Z. Deng. 2006. Utilization of the methoxymalonyl-acyl carrier protein biosynthesis locus for cloning the oxazolomycin biosynthetic gene cluster from Streptomyces albus JA3453. J Bacteriol 188:4142-7.
109. Zhou, Y., J. Li, J. Zhu, S. Chen, L. Bai, X. Zhou, H. Wu, and Z. Deng. 2008. Incomplete beta-ketone processing as a mechanism for polyene structural variation in the FR-008/candicidin complex. Chem Biol 15:629-38.
110. Zielinski J, B.-B. H., Golik J, Gumieniak J, Ziminski T,, and P. J. Kolodzi-Ejczyk P, Borwoski E. 1979. The structure of levorin A2 and candicidin D. Tetrahedron Lett 20:1791–1794.
111. Zotchev, S. B. 2003. Polyene macrolide antibiotics and their applications in human therapy. Curr Med Chem 10:211-23.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |