以计算机辅助分子设计方法改造谷氨酸脱羧酶的研究
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
谷氨酸脱羧酶(glutamate decarboxylase,简称GAD)广泛存在于动物、植物、微生物,是Y.氨基丁酸(γ-aminobutyric acid,简称GAB A)生物合成过程中的关键酶。GABA具有延缓大脑衰老、降低血压、镇定安神等生理活性,作为一种新型的功能性因子,在食品、医疗、农业等行业具有广泛的应用前景。
     目前,GAD在大规模生物合成GABA的应用方面主要有两个限制因素:第一,GAD的最适pH通常为酸性,而在酸性pH下底物L-谷氨酸的溶解度非常小;第二,酶蛋白极易热失活,不能通过提高温度的方式加快反应速率。基于短乳杆菌GAD在GABA生物合成领域的应用前景,以突破天然酶的瓶颈、获得可商业用于高效生物制备GABA的理想催化剂为目标,论文以短乳杆菌GAD为亲本,采用同源模建、分子对接以及酶分子设计的生物信息学手段对GAD进行了分子改造。
     论文首先建立了一种可用于GAD酶活性高通量筛选的显色检测法。根据GAD催化脱羧反应时会不断消耗质子这一特点,采用pKa值基本一致的溴甲酚绿指示剂和醋酸缓冲液体系,将因质子消耗引起的体系pH值升高通过指示剂颜色的变化反映出来,颜色的变化进一步用620nm波长处的吸光度变化得以量化表征,从而实现酶促反应速率与吸光度变化速率之间的线性关联。最终得到的酶促反应速率计算公式为
     第二,以E. coli GadB为模板,采用同源模建技术构建了短乳杆菌GAD的结构模型,比较了MODLLER和Swiss Model这两种不同方式对模建结果的影响,并用PROCHECK、ERRAT及ProSA程序对所得模型进行构象和能量评价。以GAD结构模型为依据,对酶活性中心进行分析后发现一些重要的功能残基:Phe65和Thr215构成了疏水的底物入口,决定着底物分子进入活性中心时的取向;Lys279、Asp248对酶的催化过程有直接的贡献;Ser127、Asp248、His278、Lys279以及PLP磷酸基团附近的α-螺旋对辅酶PLP在活性中心的定位和正确取向有着非常重要的作用。
     第三,以MODELLER构建的GAD模型为蛋白质受体,在GAD催化机制的指导下构建了模拟反应过渡态的偕二胺中间体模型,然后采用ROSETTALIGAND程序将该底物模型对接进入酶的活性中心。通过对接分析,发现Gln166和Thr64与底物分子形成氢键作用,是维持底物在酶活性中心正确位置和取向的关键。此外,L-谷氨酸的α-羧基基本处于与PLP吡啶环垂直的方向,PLP的吡啶环以磷酸基团为轴翻转了约6。,体现了脱羧反应的特点。这些结果不仅揭示了L.谷氨酸在GAD活性中心的结合模式以及活性中心重要功能残基的分布,而且也为进一步研究GAD结构和功能的关系以及酶的分子设计提供了结构模型。
     第四,观察短乳杆菌GAD的结构模型,发现酶的C末端在中性pH下阻挡了底物入口,从而抑制了酶活性。据此,构建了C末端缺失14个氨基酸的突变体GADAC。经过改造,GADAC变体酶在pH6.0下催化活性得到提高,反应2h后的GABA产量为野生型酶的4.8倍。紫外/可见光谱、荧光光谱和圆二色谱分析也显示C末端的切除改变了酶活性中心的微环境,解除了原先C末端对活性口袋的“封闭”效应。该突变酶在生物转化法连续制备GABA方面有良好的应用前景,同时也进一步阐明了短乳杆菌GAD的C末端的在酶的pH-活性调控方面作用,为GAD结构和功能的研究提供了新的线索。
     最后,为提高酶的热稳定性,提高GAD在工业上的应用价值,我们采用RosettaDesign程序,用Monte Carlo算法搜索蛋白质的序列空间,通过求取全局最小值来预测有望提高GAD热稳定性的突变位点。经过计算共得到了20个建议的突变:A63N、T64Q、C66S、I87W、I98W、I105W、K138G、M185Y、 M212W、Y216W、L226G、V229G、P240G、S249W、F256Y、V283G、 W292G、C379V、K402H、413G。用定点突变方法构建这些突变体,通过显色法初筛和HPLC法复筛,最终得到了突变酶C379V,它的半失活温度T1/2比亲本酶提高了5℃,并且酶的比活力比亲本提高了19%。疏水作用的增加是酶性能得以提高的主要原因。该研究不仅构建了更适合用于制备GABA的生物催化剂,同时也为其他酶热稳定变体的设计与改造提供了理论基础和方法保障。
Glutamate decarboxylase (GAD) is an essential enzyme widely distributed in nature from microorganisms to plants and animals. It is the key enzyme for the biosynthesis of GABA, which is useful as a functional bioactive component in food and pharmaceutical, for its anti-hypertensive and analgesic properties as well as calming effects.
     Currently the mass production of GABA in bioreactors is still limited due to the bottleneck caused by the low substrate solubility at the acidic pH optimum of GAD and the inherently thermal unstable nature of this enzyme. Based on the prospects in utilizing Lactobacillus brevis GAD for the biosynthesis of GABA, we employed bioinformatics methods such as homology modeling, molecular docking and computational enzyme design to create a more efficient biocatalyst for GABA preparation, thus breaking through the above mentioned bottleneck.
     Firstly, a pH-sensitive colorimetric assay was established to quantitatively measure GAD activity in bacterial cell extracts using a microplate format. The assay is based on the color change of bromocresol green due to an increase in pH as protons are consumed during the enzyme-catalyzed reaction. Bromocresol green was chosen as the indicator because it has a similar pKa to the acetate buffer used. The corresponding absorbance change at620nm was recorded with a microplate reader as the reaction proceeded. The enzymatic reaction rate could be calculated using the formula:v=2.4×106×dA/dt (μmol·min-1). This is a simple, economical assay that can be carried out in robotic high-throughput devices in directed evolution experiments for the rapid determination of GAD activity.
     Secondly, we constructed the homology model of Lactobacillus brevis GAD with E. coli GadB as the template using both MODELLER and Swiss Model programs. Then PROCHECK, ERRAT and ProSA were used to evaluate the quality of resulting models. The analysis of enzyme active site revealed the following functional residues:Phe65and Thr215constituted the hydrophobic substrate entrance; Asp248and Lys279directly contributed the catalysis; Serl27, Asp248, His278, Lys279and an a-helix near the PLP phosphate group were responsible for keeping the favorable position and orientation of the cofactor PLP in the active center.
     Thirdly, we modeled the geminal diamine intermediate consisting of the substrate, PLP and Lys279according to the reaction mechanism, and then docked it into GAD homo logy model using ROSETTALIGAND. A total of5000docking trajectories were generated and the best scored enzyme-substrate complex showed that the hydrogen bonds from Gln166and Thr64were of vital importance in substrate binding. Besides, the positon of a-carboxylate group of the substrate was almost pepenticular to the pyridine ring of PLP, which was rotated by approximately6°with respect to its original position, with the PLP phosphate moiety acting as an anchor. These geometries are in accord with the characteristics often observed in PLP dependent decarboxylases. This work not only revealed the binding mode of substrate in the GAD active site and the distribution of functional residues, but also provided a structure model for further study on the enzyme structure-function relationship as well as enzyme design.
     Fourthly, we speculated that the substrate entrance was probably blocked by a C-terminal tail of GAD based on the homology model, which could be the reason for no detectable enzymatic activity at neutral pH. Site-directed mutagenesis was performed to delete14C-terminal residues to generate a mutant, designated as GAD△C, which exhibited extended activity at pH6.0compared to the wild type enzyme. Comparison of the UV-visible, fluorescence and circular dichroism spectra of the mutant with those of the wild type revealed that the microenvironment of the active site had been changed and the "blocking" effect might be eliminated. These results provided evidence for the important role of C-terminal region in the pH-dependent regulation of enzymatic activity, and the resulting mutant would be useful in a bioreactor for continuous production of GABA.
     Lastly, RosettaDesign algorithm was employed with the aim of improving the thermostability of GAD. Sequence space was searched with an iterative Monte Carlo procedure, replacing a single amino acid rotamer at a time, and reevaluating the energy. With global enregy minimum found, twenty point mutations were suggested by the program:A63N, T64Q, C66S, I87W, I98W, I105W, K138G, M185Y, M212W, Y216W, L226G, V229G, P240G, S249W, F256Y, V283G, W292G, C379V, K402H and K413G. Site-directed mutagenesis was used to generate each of these mutant enzymes. After an initial screening for the enzymatic activity and a further thermal denaturation experiment, the variant C379V was selected out, which increased the T1/2by5℃, and the catalytic efficiency was enhanced by19%compared with those of the wild-type GAD. Increased hydrophobic interactions brought about by this mutation was speculated as the main reason for the improved properties. This work created a more efficient biocatalyst for GABA preparation and built the basis for the computational thermostabilization of other enzymes for industrial use.
引文
1. De Biase D, Tramonti A, Bossa F, Visca P. The response to stationary-phase stress conditions in Escherichia coli:role and regulation of the glutamic acid decarboxylase system. Molecular Microbiology 1999;32:1198-1211.
    2. Hao R, Schmit JC. Purification and characterization of glutamate decarboxylase from Neurospora crassa conidia. Journal of Biological Chemistry 1991;266:5135-5139.
    3. Shelp BJ, Bown AW, McLean MD. Metabolism and functions of gamma-aminobutyric acid. Trends in Plant Science 1999;4:446-452.
    4. Roberts E, Frankel S. y-Aminobutyric acid in brain:its formation from glutamic acid. Journal of Biological Chemistry 1950;187:55-63.
    5. Schuller HM, Al-Wadei HAN, Majidi M. Gamma-aminobutyric acid, a potential tumor suppressor for small airway-derived lung adenocarcinoma. Carcinogenesis 2008;29:1979-1985.
    6. Ting Wong CG, Bottiglieri T, Snead OC. GABA, y-hydroxybutyric acid, and neurological disease. Annals of Neurology 2003;54:S3-S12.
    7.丁一,艾华.γ-氨基丁酸与人体健康的关系.中国临床保健杂志2012:100-103.
    8. Abe Y, Umemura S, Sugimoto K, Hirawa N, Kato Y, Yokoyama N, Yokoyama T, Iwai J, lshii M. Effect of green tea rich in gamma-aminobutyric acid on blood pressure of Dahl salt-sensitive rats. American Journal of Hypertension 1995;8:74-79.
    9. Aoki H, Furuya Y, Endo Y, Fujimoto K. Effect of g-aminobutyric acid-enriched tempeh-like fermented soybean (GABA-tempeh) on the blood pressure of spontaneously hypertensive rats. Bioscience, Biotechnology, and Biochemistry 2003;67:1806-1808.
    10. Hayakawa K, Kimura M, Kasaha K, Matsumoto K, Sansawa H, Yamori Y. Effect of a y-aminobutyric acid-enriched dairy product on the blood pressure of spontaneously hypertensive and normotensive Wistar-Kyoto rats. British Journal of Nutrition 2004;92:411-417.
    11. Shizuka F, Kido Y, Nakazawa T, Kitajima H, Aizawa C, Kayamura H, Ichijo N. Antihypertensive effect of gamma-amino butyric acid enriched soy products in spontaneously hypertensive rats. Biofactors 2004;22:165-167.
    12. Nagaoka H. Treatment of germinated wheat to increase levels of GABA and IP6 catalyzed by endogenous enzymes. Biotechnology Progress 2005;21:405-410.
    13. Kono 1, Himeno K. Changes in g-aminobutyric acid content during beni-koji making. Bioscience, Biotechnology, and Biochemistry 2000;64:617-619.
    14. Tsai JS, Lin YS, Pan BS, Chen TJ. Antihypertensive peptides and y-aminobutyric acid from prozyme 6 facilitated lactic acid bacteria fermentation of soymilk. Process Biochemistry 2006;41:1282-1288.
    15.沈名灿,罗佳捷,张彬.γ-氨基丁酸在动物生产中应用的研究进展.黑龙江畜牧兽医2012:33-35.
    16.李俊凯,徐汉虹,江定心.基于γ-氨基丁酸的害虫防治策略.世界农药2006:29.31.
    17.杨东元,陈开勋,王亚红.γ-氨基丁酸的合成研究.中国饲料2010:27-28.
    18.王金玲,袁军,刘登才.γ-氨基丁酸的合成.化学与生物工程2010:40-41.
    19.穆小民,吴显荣.高等植物体内4-氨基丁酸的代谢及生理作用.氨基酸杂志1994:44.46.
    20.张晖,姚惠源,姜元荣.大米胚芽研究开发新进展.中国油脂2002:81-84.
    21. Komatsuzaki N, Tsukahara K, Toyoshima H, Suzuki T, Shimizu N, Kimura T. Effect of soaking and gaseous treatment on GABA content in germinated brown rice. Journal of Food Engineering 2007;78:556-560.
    22. Lee JY, Kim CJ, Kunz B. Identification of lactic acid bacteria isolated from kimchi and studies on their suitability for application as starter culture in the production of fermented sausages. Meat Science 2006;72:437-445.
    23. Karahan AG, Basyigit Kihc G, Kart A, Sanlidere Aloglu H, Oner Z, Aydemir S, Erkus O, Harsa S. Genotypic identification of some lactic acid bacteria by amplified fragment length polymorphism analysis and investigation of their potential usage as starter culture combinations in Beyaz cheese manufacture. Journal of Dairy Science 2010;93:1-11.
    24. Leroy F, De Vuyst L. Lactic acid bacteria as functional starter cultures for the food fermentation industry. Trends in Food Science & Technology 2004; 15:67-78.
    25. Yan PM, Xue WT, Tan SS, Zhang H, Chang XH. Effect of inoculating lactic acid bacteria starter cultures on the nitrite concentration of fermenting Chinese paocai. Food Control 2008;19:50-55.
    26. Li HX, Cao YS. Lactic acid bacterial cell factories for gamma-aminobutyric acid. Amino Acids 2010;39:1107-1116.
    27.杨丽丽,赵城彬,吴非.乳酸菌发酵米糠产γ-氨基丁酸最适条件的研究.食品工业科技2012:217.220.
    28. Li H, Qiu T, Gao D, Cao Y. Medium optimization for production of gamma-aminobutyric acid by Lactobacillus brevis NCL912. Amino Acids 2010;38:1439-1445.
    29. Park KB, Oh SH. Production and characterization of GABA rice yogurt. Food Science and Biotechnology 2005; 14:518-522.
    30. Komatsuzaki N, Nakamura T, Kimura T, Shima J. Characterization of glutamate decarboxylase from a high g-aminobutyric acid (GABA)-producer, Lactobacillus paracasei. Bioscience, Biotechnology, and Biochemistry 2008;72:278-285.
    31. Yokoyama S, Hiramatsu J, Hayakawa K. Production of y-aminobutyric acid from alcohol distillery lees by Lactobacillus brevis IFO-12005. Journal of Bioscience and Bioengineering 2002;93:95-97.
    32. Chou LS, Weimer B. Isolation and characterization of acid- and bile-tolerant isolates from strains of Lactobacillus acidophilus. Journal of Dairy Science 1999;82:23-31.
    33.梁金钟,田宇,王风青.从酸菜液中筛选产γ-氨基丁酸的菌株.食品科学2011:244-249.
    34. Kim JY, Lee MY, Ji GE, Lee YS, Hwang KT. Production of y-aminobutyric acid in black raspberry juice during fermentation by Lactobacillus brevis GABA100. International Journal of Food Microbiology 2009;130:12-16.
    35. 龚福明.豆豉中高产γ-氨基丁酸乳酸菌的筛选及其谷氨酸脱羧酶酶学特性研究.中国微生态学杂志2012;24:394-399.
    36. Sun T, Zhao S, Wang H, Cai C, Chen Y, Zhang H. ACE-inhibitory activity and gamma-aminobutyric acid content of fermented skim milk by Lactobacillus helveticus isolated from Xinjiang koumiss in China. European Food Research and Technology 2009;228:607-612.
    37. Park KB, Oh SH. Cloning, sequencing and expression of a novel glutamate decarboxylase gene from a newly isolated lactic acid bacterium, Lactobacillus brevis OPK-3. Bioresource Technology 2007;98:312-319.
    38.傅元欣,张涛,江波,沐万孟.乳酸菌细胞转化法制备γ-氨基丁酸的研究.食品工业科技2008:166.169.
    39. Nomura M, Kimoto H, Someya Y, Furukawa S, Suzuki I. Production of y-aminobutyric acid by cheese starters during cheese ripening. Journal of Dairy Science 1998;81:1486-1491.
    40. Lu X, Chen Z, Gu Z, Han Y. Isolation of y-aminobutyric acid-producing bacteria and optimization of fermentative medium. Biochemical Engineering Journal 2008;41:48-52.
    41. Yang SY, Lu FX, Lu ZX, Bie XM, Jiao Y, Sun LJ, Yu B. Production of y-aminobutyric acid by Streptococcus salivarius subsp. thermophilus Y2 under submerged fermentation. Amino Acids 2008;34:473-478.
    42.黄俊.利用短乳杆菌制备γ-氨基丁酸相关过程研究[博士学位论文].杭州:浙江大学.2006.
    43. Siragusa S, De Angelis M, Di Cagno R, Rizzello CG, Coda R, Gobbetti M. Synthesis of y-aminobutyric acid by lactic acid bacteria isolated from a variety of italian cheeses. Applied and Environmental Microbiology 2007;73:7283-7290.
    44. Roberts E, Frankel S. Glutamic acid decarboxylase in brain. Journal of Biological Chemistry 1951;188:789-795.
    45. Bu DF, Erlander MG, Hitz BC, Tillakaratne NJ, Kaufman DL, Wagner-McPherson CB, Evans GA, Tobin AJ. Two human glutamate decarboxylases,65-kDa GAD and 67-kDa GAD, are each encoded by a single gene. Proceedings of the National Academy of Sciences of the United States of America 1992;89:2115-2119.
    46. Zimmet P. Antibodies to glutamic acid decarboxylase in the prediction of insulin dependency. Diabetes Research and Clinical Practice 1996;34:S125-S131.
    47.穆小民,沈黎明,吴显荣.高等植物体内γ-氨基丁酸代谢的酶学研究进展(综述).中国农业大学学报1996:29-33.
    48. Inatomi K, Slaughter JC. Glutamate decarboxylase from barley embryos and roots. General properties and the occurrence of three enzymic forms. Biochemical Journal 1975; 147:479-484.
    49. Zhang H, Yao H, Chen F, Wang X. Purification and characterization of glutamate decarboxylase from rice germ. Food Chemistry 2007; 101:1670-1676.
    50. Matsumoto T, Yamaura I, Funatsu M. Purification and properties of glutamate decarboxylase from squash. Agricultural and biological chemistry 1986;50:1413-1417.
    51. Satyanarayan V, Nair PM. Purification and characterization of glutamate decarboxylase from Solanum tuberosum. European Journal of Biochemistry 1985;150:53-60.
    52. Johnson BS, Singh NK, Cherry JH, Locy RD. Purification and characterization of glutamate decarboxylase from cowpea. Phytochemistry 1997:46:39-44.
    53.范军,李纯,朱苏文,程备久.小麦谷氨酸脱羧酶的纯化及部分性质研究.中国生物化学与分子生物学报1998:175-178.
    54. Baum G, Lev-Yadun S, Fridmann Y, Arazi T, Katsnelson H, Zik M, Fromm H. Calmodulin binding to glutamate decarboxylase is required for regulation of glutamate and GABA metabolism and normal development in plants. The EMBO Journal 1996;15:2988-2996.
    55. Streeter JG, Thompson JF. Anaerobic accumulation of gamma-aminobutyric acid and alanine in radish leaves (Raphanus sativus L.). Plant Physiology 1972;49:572-578.
    56. Rhodes D, Handa S, Bressan RA. Metabolic changes associated with adaptation of plant cells to water stress. Plant Physiology 1986;82:890-903.
    57. Mayer RR, Cherry JH, Rhodes D. Effects of heat shock on amino acid metabolism of cowpea cells. Plant Physiology 1990;94:796-810.
    58. Crawford LA, Bown AW, Breitkreuz KE, Guinel FC. The synthesis of g-aminobutyric acid in response to treatments reducing cytosolic pH. Plant Physiology 1994; 104:865-871.
    59. Wallace W, Secor J, Schrader LE. Rapid accumulation of γ-aminobutyric acid and alanine in soybean leaves in response to an abrupt transfer to lower temperature, darkness, or mechanical manipulation. Plant Physiology 1984;75:170-175.
    60. Aurisano N, Bertani A, Reggiani R. Anaerobic accumulation of 4-aminobutyrate in rice seedlings; Causes and significance. Phytochemistry 1995;38:1147-1150.
    61. Yang T, Chaudhuri S, Yang L, Chen Y, Poovaiah BW. Calcium/Calmodulin up-regulates a cytoplasmic receptor-like kinase in plants. Journal of Biological Chemistry 2004;279:42552-42559.
    62. Snedden WA, Arazi T, Fromm H, Shelp BJ. Calcium/Calmodulin activation of soybean glutamate decarboxylase. Plant Physiology 1995;108:543-549.
    63. Snedden WA, Koutsia N, Baum G, Fromm H. Activation of a recombinant petunia glutamate decarboxylase by calcium/calmodulin or by a monoclonal antibody which recognizes the calmodulin binding domain. Journal of Biological Chemistry 1996;271:4148-4153.
    64. Tsuchiya K, Nishimura K, Iwahara M. Purification and characterization of glutamate decarboxylase from Aspergillus oryzae. Food Science and Technology Research 2003;9:283-287.
    65. O' Leary MH, Richards DT, Hendrickson DW. Carbon isotope effects on the enzymic decarboxylation of glutamic acid. Journal of the American Chemical Society 1970:92:4435-4440.
    66. Strausbauch PH, Fischer EH. Structure of the binding site of pyridoxal 5'-phosphate to Escherichia coli glutamate decarboxylase. Biochemistry 1970;9:233-238.
    67. Strausbauch PH, Fischer EH. Chemical and physical properties of Escherichia coli glutamate decarboxylase. Biochemistry 1970;9:226-233.
    68. Maras B, Sweeney G, Barra D, Bossa F, John RA. The amino acid sequence of glutamate decarboxylase from Escherichia coli. European Journal of Biochemistry 1992;204:93-98.
    69. Smith DK, Kassam T, Singh B, Elliott JF. Escherichia coli has two homologous glutamate decarboxylase genes that map to distinct loci. Journal of Bacteriology 1992; 174:5820-5826.
    70. Malashkevich VN, De Biase D, Markovic-Housley Z, Schlunegger MP, Bossa F, Jansonius JN. Crystallization and preliminary X-ray analysis of the b-isoform of glutamate decarboxylase from Escherichia coli. Acta Crystallographica Section D 1998;54:1020-1022.
    71. Capitani G, De Biase D, Aurizi C, Gut H, Bossa F, Grutter MG. Crystal structure and functional analysis of Escherichia coli glutamate decarboxylase. The EMBO Journal 2003;22:4027-4037.
    72. Foster JW. Escherichia coli acid resistance:tales of an amateur acidophile. Nature Reviews Microbiology 2004;2:898-907.
    73. Gut H, Pennacchietti E, John RA, Bossa F, Capitani G, De Biase D, Grutter MG. Escherichia coli acid resistance:pH-sensing, activation by chloride and autoinhibition in GadB. The EMBO Journal 2006;25:2643-2651.
    74. Ueno Y, Hayakawa K, Takahashi S, Oda K. Purification and characterization of glutamate decarboxylase from Lactobacillus brevis IFO 12005. Bioscience, Biotechnology, and Biochemistry 1997;61:1168-1171.
    75.许建军,江波,许时婴.Lactococcus lactis谷氨酸脱羧酶的分离纯化及部分酶学性质.无锡轻工大学学报2004:79.84.
    76. Huang J, Mei L, Sheng Q, Yao S, Lin D. Purification and characterization of glutamate decarboxylase of Lactobacillus brevis CGMCC 1306 isolated from fresh milk. Chinese Journal of Chemical Engineering 2007; 15:157-161.
    77. Nomura M, Nakajima I, Fujita Y, Kobayashi M, Kimoto H, Suzuki I, Aso H. Lactococcus lactis contains only one glutamate decarboxylase gene. Microbiology 1999;145:1375-1380.
    78. Fan E, Huang J, Hu S, Mei L, Yu K. Cloning, sequencing and expression of a glutamate decarboxylase gene from the GABA-producing strain CGMCC 1306. Annals of Microbiology 2012;62:689-698.
    79. Arnold FH. Directed evolution:Creating biocatalysts for the future. Chemical Engineering Science 1996;51:5091-5102.
    80. Arnold FH, Georgiou G. Directed evolution library creation. New York:Humana Press. 2003;231:3-9.
    81. Cadwell RC, Joyce GF. Randomization of genes by PCR mutagenesis. Genome Research 1992;2:28-33.
    82. Stemmer WPC. Rapid evolution of a protein in vitro by DNA shuffling. Nature 1994:370:389-391.
    83. Stemmer WPC. DNA shuffling by random fragmentation and reassembly:in vitro recombination for molecular evolution. Proceedings of the National Academy of Sciences of the United States of America 1994;91:10747-10751.
    84. Zhao H, Giver L, Shao Z, Affholter JA, Arnold FH. Molecular evolution by staggered extension process (StEP) in vitro recombination. Nature Biotechnology 1998;16:258-261.
    85. Shao Z, Zhao H, Giver L, Arnold FH. Random-priming in vitro recombination:An effective tool for directed evolution. Nucleic Acids Research 1998:26:681-683.
    86. Coco WM, Levinson WE, Crist MJ, Hektor HJ, Darzins A, Pienkos PT, Squires CH, Monticello DJ. DNA shuffling method for generating highly recombined genes and evolved enzymes. Nature Biotechnology 2001;19:354-359.
    87. Fujii R, Kitaoka M, Hayashi K. RAISE:a simple and novel method of generating random insertion and deletion mutations. Nucleic Acids Research 2006;34:e30.
    88. Lipovsek D, Antipov E, Armstrong KA, Olsen MJ, Klibanov AM, Tidor B, Wittrup KD. Selection of horseradish peroxidase variants with enhanced enantioselectivity by yeast surface display. Chemistry & Biology 2007;14:1176-1185.
    89. Olsen MJ, Stephens D, Griffiths D, Daugherty P, Georgiou G, Iverson BL. Function-based isolation of novel enzymes from a large library. Nature Biotechnology 2000; 18:1071-1074.
    90. Wang M, Si T, Zhao H. Biocatalyst development by directed evolution. Bioresource Technology 2012; 115:117-125.
    91. Wong TS, Zhurina D, Schwaneberg U. The diversity challenge in directed protein evolution. Combinatorial Chemistry & High Throughput Screening 2006;9:271-288.
    92. Reetz MT, Carballeira JD. Iterative saturation mutagenesis (ISM) for rapid directed evolution of functional enzymes. Nature Protocols 2007;2:891-903.
    93. Lutz S. Beyond directed evolution—semi-rational protein engineering and design. Current Opinion in Biotechnology 2010;21:734-743.
    94. Pavelka A, Chovancova E, Damborsky J. HotSpot Wizard:a web server for identification of hot spots in protein engineering. Nucleic Acids Research 2009;37:W376-W383.
    95. Kuipers RK, Joosten HJ, van Berkel WJH, Leferink NGH, Rooijen E, Ittmann E, van Zimmeren F, Jochens H, Bornscheuer U, Vriend G, Martins dos Santos VAP, Schaap PJ. 3DM:Systematic analysis of heterogeneous superfamily data to discover protein functionalities. Proteins:Structure, Function, and Bioinformatics 2010;78:2101-2113.
    96. Jochens H, Bornscheuer UT. Natural diversity to guide focused directed evolution. ChemBioChem 2010;11:1861-1866.
    97. Ehren J, Govindarajan S, Moron B, Minshull J, Khosla C. Protein engineering of improved prolyl endopeptidases for celiac sprue therapy. Protein Engineering Design and Selection 2008;21:699-707.
    98. Pavlova M, Klvana M, Prokop Z, Chaloupkova R, Banas P, Otyepka M, Wade RC, Tsuda M, Nagata Y, Damborsky J. Redesigning dehalogenase access tunnels as a strategy for degrading an anthropogenic substrate. Nature Chemical Biology 2009;5:727-733.
    99. Heinzelman P, Snow CD, Wu I, Nguyen C, Villalobos A, Govindarajan S, Minshull J, Arnold FH. A family of thermostable fungal cellulases created by structure-guided recombination. Proceedings of the National Academy of Sciences of the United States of America 2009;106:5610-5615.
    100. Wu S, Acevedo JP, Reetz MT. Induced allostery in the directed evolution of an enantioselective Baeyer-Villiger monooxygenase. Proceedings of the National Academy of Sciences of the United States of America 2010;107:2775-2780.
    101. Rui L, Cao L, Chen W, Reardon KF, Wood TK. Active site engineering of the epoxide hydrolase from Agrobacterium radiobacter AD1 to enhance aerobic mineralization of cis-1,2-dichloroethylene in cells expressing an evolved toluene ortho-monooxygenase. Journal of Biological Chemistry 2004;279:46810-46817.
    102.来鲁华,徐筱杰,唐有祺.蛋白质的结构预测和分子设计.自然科学进展1995:4-8.
    103. Tuckerman ME, Martyna GJ. Understanding modern molecular dynamics:Techniques and applications. The Journal ofPhysical Chemistry B 1999;104:159-178.
    104. Gao J, Truhlar DG. Quantum mechanical methods for enzyme kinetics. Annual Review of Physical Chemistry 2002;53:467-505.
    105. Larkin MA, Blackshields G, Brown NP, Chenna R, McGettigan PA, Mc William H, Valentin F, Wallace IM, Wilm A, Lopez R, Thompson JD, Gibson TJ, Higgins DG. Clustal W and Clustal X version 2.0. Bioinformatics 2007;23:2947-2948.
    106. Altschul SF, Gish W, Miller W, Myers EW, Lipman DJ. Basic local alignment search tool. Journal of Molecular Biology 1990;215:403-410.
    107. Holm L, Rosenstrom P. Dali server:conservation mapping in 3D. Nucleic Acids Research 2010;38:W545-W549.
    108. Laskowski RA, MacArthur MW, Moss DS, Thornton JM. PROCHECK:a program to check the stereochemical quality of protein structures. Journal of Applied Crystallography 1993;26:283-291.
    109. Wiederstein M, Sippl MJ. ProSA-web:interactive web service for the recognition of errors in three-dimensional structures of proteins. Nucleic Acids Research 2007;35:W407-W410.
    110. Luthy R, Bowie JU, Eisenberg D. Assessment of protein models with three-dimensional profiles. Nature 1992;356:83-85.
    111. Scott WRP, Hunenberger PH, Tironi IG, Mark AE, Billeter SR, Fennen J, Torda AE, Huber T, Kruger P, van Gunsteren WF. The GROMOS biomolecular simulation program package. The Journal of Physical Chemistry A 1999;103:3596-3607.
    112. Van Der Spoel D, Lindahl E, Hess B, Groenhof G, Mark AE, Berendsen HJC. GROMACS: Fast, flexible, and free. Journal of Computational Chemistry 2005;26:1701-1718.
    113. Case DA, Cheatham TE, Darden T, Gohlke H, Luo R, Merz KM, Onufriev A, Simmerling C, Wang B, Woods RJ. The Amber biomolecular simulation programs. Journal of Computational Chemistry 2005;26:1668-1688.
    114. Brooks BR, Brooks CL, Mackerell AD, Nilsson L, Petrella RJ, Roux B, Won Y, Archontis G, Bartels C, Boresch S, Caflisch A, Caves L, Cui Q, Dinner AR, Feig M, Fischer S, Gao J, Hodoscek M, Im W, Kuczera K, Lazaridis T, Ma J, Ovchinnikov V, Paci E, Pastor RW, Post CB, Pu JZ, Schaefer M, Tidor B, Venable RM, Woodcock HL, Wu X, Yang W, York DM, Karplus M. CHARMM:The biomolecular simulation program. Journal of Computational Chemistry 2009;30:1545-1614.
    115. Goodsell DS, Morris GM, Olson AJ. Automated docking of flexible ligands:Applications of AutoDock. Journal of Molecular Recognition 1996;9:1-5.
    116. Ewing TJA, Makino S, Skillman AG, Kuntz ID. DOCK 4.0:Search strategies for automated molecular docking of flexible molecule databases. Journal of Computer-Aided Molecular Design 2001;15:411-428.
    117. Friesner RA, Banks JL, Murphy RB, Halgren TA, Klicic JJ, Mainz DT, Repasky MP, Knoll EH, Shelley M, Perry JK, Shaw DE, Francis P, Shenkin PS. Glide:A new approach for rapid, accurate docking and scoring.1. Method and assessment of docking accuracy. Journal of Medicinal Chemistry 2004;47:1739-1749.
    118. Schmidt MW, Baldridge KK, Boatz JA, Elbert ST, Gordon MS, Jensen JH, Koseki S, Matsunaga N, Nguyen KA, Su S, Windus TL, Dupuis M, Montgomery JA. General atomic and molecular electronic structure system. Journal of Computational Chemistry 1993;14:1347-1363.
    119. Stewart JJP. Optimization of parameters for semiempirical methods I. Method. Journal of Computational Chemistry 1989; 10:209-220.
    120. Looger LL, Dwyer MA, Smith JJ, Hellinga HW. Computational design of receptor and sensor proteins with novel functions. Nature 2003;423:185-190.
    121. Kortemme T, Baker D. Computational design of protein-protein interactions. Current Opinion in Chemical Biology 2004;8:91-97.
    122. Ashworth J, Havranek JJ, Duarte CM, Sussman D, Monnat Jr RJ, Stoddard BL, Baker D. Computational redesign of endonuclease DNA binding and cleavage specificity. Nature 2006;441:656-659.
    123. Thyme SB, Jarjour J, Takeuchi R, Havranek JJ, Ashworth J, Scharenberg AM, Stoddard BL, Baker D. Exploitation of binding energy for catalysis and design. Nature 2009;461:1300-1304.
    124. Kuhlman B, Dantas G, Ireton GC, Varani G, Stoddard BL, Baker D. Design of a Novel Globular Protein Fold with Atomic-Level Accuracy. Science 2003;302:1364-1368.
    125. Gribenko AV, Patel MM, Liu J, McCallum SA, Wang C, Makhatadze GI. Rational stabilization of enzymes by computational redesign of surface charge-charge interactions. Proceedings of the National Academy of Sciences of the United States of America 2009;106:2601-2606.
    126. Korkegian A, Black ME, Baker D, Stoddard BL. Computational Thermostabilization of an Enzyme. Science 2005;308:857-860.
    127. DeGrado WF. Computational biology:Biosensor design. Nature 2003;423:132-133.
    128. Chen CY, Georgiev I, Anderson AC, Donald BR. Computational structure-based redesign of enzyme activity. Proceedings of the National Academy of Sciences of the United States of America 2009; 106:3764-3769.
    129. Khoury GA, Fazelinia H, Chin JW, Pantazes RJ, Cirino PC, Maranas CD. Computational design of Candida boidinii xylose reductase for altered cofactor specificity. Protein Science 2009;18:2125-2138.
    130. Murphy PM, Bolduc JM, Gallaher JL, Stoddard BL, Baker D. Alteration of enzyme specificity by computational loop remodeling and design. Proceedings of the National Academy of Sciences of the United States of America 2009;106:9215-9220.
    131. Yeung N, Lin YW, Gao YG, Zhao X, Russell BS, Lei L, Miner KD, Robinson H, Lu Y. Rational design of a structural and functional nitric oxide reductase. Nature 2009;462:1079-1082.
    132. Siegel JB, Zanghellini A, Lovick HM, Kiss G, Lambert AR, St.Clair JL, Gallaher JL, Hilvert D, Gelb MH, Stoddard BL, Houk KN, Michael FE, Baker D. Computational design of an enzyme catalyst for a stereoselective bimolecular diels-alder reaction. Science 2010;329:309-313.
    133. Kravitz EA. Enzymic formation of gamma-aminobutyric acid in the peripheral and central nervous system of lobsters. Journal of Neurochemistry 1962;9:363-370.
    134. Lupien PJ, Hinse CM, Berlinguet L. Determination of glutamic acid decarboxylase activity in rat brain. Analytical Biochemistry 1968;24:1-8.
    135. Park KB, Oh SH. Production and characterization of GABA rice yogurt. Food Science and Biotechnology 2005; 14:518-522.
    136. Li H, Qiu T, Cao Y, Yang J, Huang Z. Pre-staining paper chromatography method for quantification of y-aminobutyric acid. Journal of Chromatography A 2009;1216:5057-5060.
    137. Lowe IP, Robins E, Eyerman GS. The fluorometric measurement of glutamic decarboxylase and its distribution in brain. Journal of Neurochemistry 1958;3:8-18.
    138. De Biase D, Tramonti A, John RA, Bossa F. Isolation, overexpression, and biochemical characterization of the two isoforms of glutamic acid decarboxylase from Escherichia coli. Protein Expression and Purification 1996;8:430-438.
    139. Tsukatani T, Higuchi T, Matsumoto K. Enzyme-based microtiter plate assay for y-aminobutyric acid:Application to the screening of γ-aminobutyric acid-producing lactic acid bacteria. Analytica Chimica Acta 2005;540:293-297.
    140. Cozzani I. Spectrophotometric assay of L-glutamic acid decarboxylase. Analytical Biochemistry 1970;33:125-131.
    141. Salvadori C, Fasella P. Determination of glutamic acid decarboxylase activity using a PH-STAT apparatus. Italian Journal of Biochemistry 1970;19:193-203.
    142. Eisenthal R, Danson M. Enzyme assays:A practical approach. New York:Oxford University Press.1992:59-92.
    143. Rosenberg RM, Herreid RM, Piazza GJ, O' Leary MH. Indicator assay for amino acid decarboxylases. Analytical Biochemistry 1989;181:59-65.
    144. Gibbons BH, Edsall JT. Rate of hydration of carbon dioxide and dehydration of carbonic acid at 25 degrees. Journal of Biological Chemistry 1963;238:3502-3507.
    145. Darrow RA, Colowick SP. Hexokinase from Baker's yeast. ATP+Hexose→ADP+Hexose-6-phosphate+H+. Methods in Enzymology 1962;5:226-235.
    146. Persson M, Palcic MM. A high-throughput pH indicator assay for screening glycosyltransferase saturation mutagenesis libraries. Analytical Biochemistry 2008;378:1-7.
    147. Lowry OH, Roberts NR, Wu ML, Hixon WS, Crawford EJ. The quantitative histochemistry of brain. II. Enzyme measurements. Journal of Biological Chemistry 1954;207:19-37.
    148. Banerjee A, Kaul P, Sharma R, Banerjee UC. A high-throughput amenable colorimetric assay for enantioselective screening of nitrilase-producing microorganisms using pH sensitive indicators. Journal of Biomolecular Screening 2003;8:559-565.
    149. Holloway P, Trevors JT, Lee H. A colorimetric assay for detecting haloalkane dehalogenase activity. Journal of Microbiological Methods 1998;32:31-36.
    150. Janes LE, Lowendahl AC, Kazlauskas RJ. Quantitative screening of hydrolase libraries using pH indicators:Identifying active and enantioselective hydrolases. Chemistry-A European Journal 1998;4:2324-2331.
    151. Martinez-Martinez I, Montoro-Garcia S, Lozada-Ramirez JD, Sanchez-Ferrer A, Garcia-Carmona F. A colorimetric assay for the determination of acetyl xylan esterase or cephalosporin C acetyl esterase activities using 7-amino cephalosporanic acid, cephalosporin C, or acetylated xylan as substrate. Analytical Biochemistry 2007;369:210-217.
    152. Moris-Varas F, Shah A, Aikens J, Nadkarni NP, Rozzell JD, Demirjian DC. Visualization of enzyme-catalyzed reactions using pH indicators:Rapid screening of hydrolase libraries and estimation of the enantioselectivity. Bioorganic and Medicinal Chemistry 1999;7:2183-2188.
    153. Whittaker RG, Manthey MK, Le Brocque DS, Hayes PJ. A microtiter plate assay for the characterization of serine proteases by their esterase activity. Analytical Biochemistry 1994;220:238-243.
    154. Chapman E, Wong CH. A pH sensitive colorometric assay for the high-throughput screening of enzyme inhibitors and substrates:A case study using kinases. Bioorganic and Medicinal Chemistry 2002;10:551-555.
    155. Khalifah RG. The carbon dioxide hydration activity of carbonic anhydrase. I. Stop-flow kinetic studies on the native human isoenzymes B and C. Journal of Biological Chemistry 1971;246:2561-2573.
    156. Salazar O, Sun L. Evaluating a screen and analysis of mutant libraries. Methods in Molecular Biology 2003;230:85-97.
    157.李明,苏显中,于敏,郑全喜.蛋白质结构预测研究进展.生物技术2009:87.90.
    158. Rodriguez R, Chinea G, Lopez N, Pons T, Vriend G. Homology modeling, model and software evaluation:three related resources. Bioinformatics 1998; 14:523-528.
    159. Eswar N, Webb B, Marti-Renom MA, Madhusudhan MS, Eramian D, Shen M, Pieper U, Sali A. Current protocols in protein science. Hoboken:John Wiley & Sons, Inc.2001.
    160. Bordoli L, Kiefer F, Arnold K, Benkert P, Battey J, Schwede T. Protein structure homology modeling using SWISS-MODEL workspace. Nature Protocols 2008;4:1-13.
    161. Colovos C, Yeates TO. Verification of protein structures:Patterns of nonbonded atomic interactions. Protein Science 1993:2:1511-1519.
    162. Ramachandran GN, Ramakrishnan C, Sasisekharan V. Stereochemistry of polypeptide chain configurations. Journal of Molecular Biology 1963;7:95-99.
    163. Kleywegt GJ, Jones TA. Phi/psi-chology:Ramachandran revisited. Structure 1996;4:1395-1400.
    164. Boberg J, Salakoski T, Vihinen M. Selection of a representative set of structures from Brookhaven Protein Data Bank. Proteins:Structure, Function, and Bioinformatics 1992;14:265-276.
    165. Percudani R, Peracchi A. A genomic overview of pyridoxal-phosphate-dependent enzymes. EMBO reports 2003;4:850-854.
    166. Christen P, Mehta PK. From cofactor to enzymes. The molecular evolution of pyridoxal-5'-phosphate-dependent enzymes. The Chemical Record 2001;1:436-447.
    167. Schneider G, Kack H, Lindqvist Y. The manifold of vitamin B6 dependent enzymes. Structure 2000;8:R1-R6.
    168. Jansonius JN. Structure, evolution and action of vitamin B6-dependent enzymes. Current Opinion in Structural Biology 1998:8:759-769.
    169. Capitani G, Biase DD, Aurizi C, Gut H, Bossa F, Grutter MG. Crystal structure and functional analysis of Escherichia coli glutamate decarboxylase. The EMBO Journal 2003:22:4027-4037.
    170. John RA. Pyridoxal phosphate-dependent enzymes. Biochimica et Biophysica Acta 1995:1248:81-96.
    171. Mozzarelli A, Bettati S. Exploring the pyridoxal 5'-phosphate-dependent enzymes. The Chemical Record 2006;6:275-287.
    172. Momany C, Ghosh R, Hackert ML. Structural motifs for pyridoxal-5'-phosphate binding in decarboxylases:An analysis based on the crystal structure of the Lactobacillus 30a ornithine decarboxylase. Protein Science 1995;4:849-854.
    173. Denessiouk KA, Denesyuk AI, Lehtonen JV, Korpela T, Johnson MS. Common structural elements in the architecture of the cofactor-binding domains in unrelated families of pyridoxal phosphate-dependent enzymes. Proteins:Structure, Function, and Bioinformatics 1999;35:250-261.
    174. Kuntz ID, Blaney JM, Oatley SJ, Langridge R, Ferrin TE. A geometric approach to macromolecule-ligand interactions. Journal of Molecular Biology 1982;161:269-288.
    175.段爱霞,陈晶,刘宏德,刘秀辉,卢小泉.分子对接方法的应用与发展.分析科学学报2009:473.477.
    176. Fischer E. Einfluss der configuration auf die wirkung der enzyme. Berichte der Deutschen Chemischen Gesellschaft 1894;27:2985-2993.
    177. Koshland DE. Application of a theory of enzyme specificity to protein synthesis. Proceedings of the National Academy of Sciences of the United States of America 1958;44:98-104.
    178. Halperin I, Ma B, Wolfson H, Nussinov R. Principles of docking:An overview of search algorithms and a guide to scoring functions. Proteins:Structure, Function, and Bioinformatics 2002;47:409-443.
    179.王存新,常珊,龚新奇,杨峰,李春华,陈慰祖.蛋白质-蛋白质分子对接中打分函数研究进展.物理化学学报2012:751-758.
    180. Cornell WD, Cieplak P, Bayly CI, Gould IR, Merz KM, Ferguson DM, Spellmeyer DC, Fox T, Caldwell JW, Kollman PA. A second generation force field for the simulation of proteins, nucleic acids, and organic molecules. Journal of the American Chemical Society 1995;117:5179-5197.
    181. Vanommeslaeghe K, Hatcher E, Acharya C, Kundu S, Zhong S, Shim J, Darian E, Guvench O, Lopes P, Vorobyov I, Mackerell AD. CHARMM general force field:A force field for drug-like molecules compatible with the CHARMM all-atom additive biological force fields. Journal of Computational Chemistry 2010;31:671-690.
    182. Wang R, Lai L, Wang S. Further development and validation of empirical scoring functions for structure-based binding affinity prediction. Journal of Computer-Aided Molecular Design 2002; 16:11-26.
    183. Gohlke H, Hendlich M, Klebe G. Knowledge-based scoring function to predict protein-ligand interactions. Journal of Molecular Biology 2000:295:337-356.
    184. Eldridge MD, Murray CW, Auton TR, Paolini GV, Mee RP. Empirical scoring functions:I. The development of a fast empirical scoring function to estimate the binding affinity of ligands in receptor complexes. Journal of Computer-Aided Molecular Design 1997;11:425-445.
    185. Murray CW, Auton TR, Eldridge MD. Empirical scoring functions.11. The testing of an empirical scoring function for the prediction of ligand-receptor binding affinities and the use of Bayesian regression to improve the quality of the model. Journal of Computer-Aided Molecular Design 1998;12:503-519.
    186. Gehlhaar DK, Verkhivker GM, Rejto PA, Sherman CJ, Fogel DB, Fogel LJ, Freer ST. Molecular recognition of the inhibitor AG-1343 by HIV-1 protease:Conformationally flexible docking by evolutionary programming. Chemistry and Biology 1995;2:317-324.
    187. Luty BA, Wasserman ZR, Stouten PFW, Hodge CN, Zacharias M, McCammon JA. A molecular mechanics/grid method for evaluation of ligand-receptor interactions. Journal of Computational Chemistry 1995; 16:454-464.
    188. Venkatachalam CM, Jiang X, Oldfield T, Waldman M. LigandFit:a novel method for the shape-directed rapid docking of ligands to protein active sites. Journal of Molecular Graphics and Modelling 2003;21:289-307.
    189. Jones G, Willett P, Glen RC, Leach AR, Taylor R. Development and validation of a genetic algorithm for flexible docking. Journal of Molecular Biology 1997:267:727-748.
    190. Rarey M, Kramer B, Lengauer T, Klebe G. A fast flexible docking method using an incremental construction algorithm. Journal of Molecular Biology 1996;261:470-489.
    191. Rester U. Dock around the clock-Current status of small molecule docking and scoring. QSAR and Combinatorial Science 2006;25:605-615.
    192. Taylor RD, Jewsbury PJ, Essex JW. A review of protein-small molecule docking methods. Journal of Computer-Aided Molecular Design 2002;16:151-166.
    193. Warren GL, Andrews CW, Capelli AM, Clarke B, LaLonde J, Lambert MH, Lindvall M, Nevins N, Semus SF, Senger S, Tedesco G, Wall ID, Woolven JM, Peishoff CE, Head MS. A critical assessment of docking programs and scoring functions. Journal of Medicinal Chemistry 2006;49:5912-5931.
    194. Sousa SF, Fernandes PA, Ramos MJ. Protein-ligand docking:Current status and future challenges. Proteins:Structure, Function, and Bioinformatics 2006;65:15-26.
    195. Meiler J, Baker D. ROSETTALIGAND:protein-small molecule docking with full side-chain flexibility. Proteins:Structure, Function, and Bioinformatics 2006;65:538-548.
    196. Dunbrack Jr RL, Cohen FE. Bayesian statistical analysis of protein side-chain rotamer preferences. Protein Science 1997;6:1661-1681.
    197. Hawkins PCD, Skillman AG, Warren GL, Ellingson BA, Stahl MT. Conformer generation with omega:Algorithm and validation using high quality structures from the protein databank and cambridge structural database. Journal of Chemical Information and Modeling 2010;50:572-584.
    198. Kuhlman B, Baker D. Native protein sequences are close to optimal for their structures. Proceedings of the National Academy of Sciences of the United States of America 2000;97:10383-10388.
    199. Jurnak FA, McPherson A. Biological macromolecules & assemblies:Active sites of enzymes. New York:John Wiley & Sons, Inc.1987:3:187-285.
    200. Hermann JC, Ghanem E, Li Y, Raushel FM, Irwin JJ, Shoichet BK. Predicting substrates by docking high-energy intermediates to enzyme structures. Journal of the American Chemical Society 2006;128:15882-15891.
    201. Kairys V, Fernandes MX, Gilson MK. Screening drug-like compounds by docking to homology models:A systematic study. Journal of Chemical Information and Modeling 2005;46:365-379.
    202. Kaufmann KW, Meiler J. Using RosettaLigand for small molecule docking into comparative models. PLoS ONE 2012;7:e50769.
    203. Schirch L. Serine transhydroxymethylase. Relaxation and transient kinetic study of the formation and interconversion of the enzyme-glycine complexes. Journal of Biological Chemistry 1975;250:1939-1945.
    204. Jackson LK, Baldwin J, Akella R, Goldsmith EJ, Phillips MA. Multiple active site conformations revealed by distant site mutation in ornithine decarboxylase. Biochemistry 2004;43:12990-12999.
    205. Karthikeyan S, Zhou Q, Zhao Z, Kao CL, Tao Z, Robinson H, Liu HW, Zhang H. Structural analysis of Pseudomonas 1-aminocyclopropane-l-carboxylate deaminase complexes: Insight into the mechanism of a unique pyridoxal-5'-phosphate dependent cyclopropane ring-opening reaction. Biochemistry 2004;43:13328-13339.
    206. Scarsdale JN, Kazanina G, Radaev S, Schirch V, Wright HT. Crystal structure of rabbit cytosolic serine hydroxymethyltransferase at 2.8 A resolution:Mechanistic implications. Biochemistry 1999;38:8347-8358.
    207. Sivaraman J, Li Y, Larocque R, Schrag JD, Cygler M, Matte A. Crystal structure of hisridinol phosphate aminotransferase (HisC) from Escherichia coli, and its covalent complex with pyridoxal-5'-phosphate and L-histidinol phosphate. Journal of Molecular Biology 2001;311:761-776.
    208. Szebenyi DME, Liu X, Kriksunov IA, Stover PJ, Thiel DJ. Structure of a murine cytoplasmic serine hydroxymethyltransferase quinonoid ternary complex:Evidence for asymmetric obligate dimers. Biochemistry 2000;39:13313-13323.
    209. Richter F, Leaver-Fay A, Khare SD, Bjelic S, Baker D. De Novo enzyme design using Rosetta3. PLoS ONE 201 1;6:e19230.
    210. Grant PL, Basford JM, John RA. An investigation of transient intermediates in the reaction of 2-methylglutamate with glutamate decarboxylase from Escherichia coli. Biochemical Journal 1987;241:699-704.
    211. Dunathan HC. Conformation and reaction specificity in pyridoxal phosphate enzymes. Proceedings of the National Academy of Sciences of the United States of America 1966;55:712-716.
    212. Dutyshev DI, Darii EL, Fomenkova NP, Pechik IV, Polyakov KM, Nikonov SV, Andreeva NS, Sukhareva BS. Structure of Escherichia coli glutamate decarboxylase (GADa) in complex with glutarate at 2.05 A resolution. Acta Crystallographica Section D 2005;61:230-235.
    213. Pennacchietti E, Lammens TM, Capitani G, Franssen MCR, John RA, Bossa F, De Biase D. Mutation of His465 alters the pH-dependent spectroscopic properties of Escherichia coli glutamate decarboxylase and broadens the range of its activity toward more alkaline pH. Journal of Biological Chemistry 2009;284:31587-31596.
    214. QuikChange II Site-Directed Mutagenesis Kit Instruction Manual. Agilent Technologies. [2012.12.20] http://www.chem.agilent.com/Library/usermanuals/Public/200523.pdf
    215. Ni-NTA Agarose Purification of 6xHis-tagged Proteins from E. coli under Native Conditions. [2013.3.20] http://www.qiagen.com/Products/Catalog/Sample-Technologies./Protein-Sample-Technologies/Purification-Kits-and-Resins/Ni-NTA-Agarose#resources.
    216. Hong S-J, Ullah I, Park G-S, Lee C, Shin J-H. Overexpression and characterization of recombinant glutamate decarboxylase from Thermococcus kodakaraensis KOD1. Journal of the Korean Society for Applied Biological Chemistry 2012:55:213-218.
    217. Shukuya R, Schwert GW. Glutamic acid decarboxylase. Ⅱ. The spectrum of the enzyme. Journal of Biological Chemistry 1960:235:1653-1657.
    218. Johnson WC. Protein secondary structure and circular dichroism:A practical guide. Proteins:Structure, Function, and Bioinformatics 1990;7:205-214.
    219. Kelly SM, Price NC. The use of circular dichroism in the investigation of protein structure and function. Current Protein and Peptide Science 2000; 1:349-384.
    220. Greenfield NJ. Applications of circular dichroism in protein and peptide analysis. Trends in Analytical Chemistry 1999;18:236-244.
    221. Vieille C, Zeikus GJ. Hyperthermophilic enzymes:Sources, uses, and molecular mechanisms for thermostability. Microbiology and Molecular Biology Reviews 2001;65:1-43.
    222. Bergquist PL, Morgan HW. The molecular genetics and biotechnological application of enzymes from extremely thermophilic eubacteria. Molecular Biology and Biotechnology of Extremophiles 1992:44-75.
    223. Lawyer FC, Stoffel S, Saiki RK, Myambo K, Drammond R, Gelfand DH. Isolation, characterization, and expression in Escherichia coli of the DNA polymerase gene from Thermus aquaticus. Journal of Biological Chemistry 1989;264:6427-6437.
    224. Burdette DS. Secundo F, Phillips RS, Dong J, Scott RA, Zeikus JG. Biophysical and mutagenic analysis of Thermoanaerobacter ethanolicus secondary-alcohol dehydrogenase activity and specificity. Biochemical Journal 1997;326:717-724.
    225. Canganella F, Andrade CM, Antranikian G. Charactevization of amylolytic and pullulytic enzymes from thermophilic archaea and from a new Fervidobacterium species. Applied Microbiology and Biotechnology 1994;42:239-245.
    226. Dong G, Vieille C, Savchenko A, Zeikus JG. Cloning, sequencing, and expression of the gene encoding extracellular a-amylase from Pyrococcus furiosus and biochemical characterization of the recombinant enzyme. Applied and Environmental Microbiology 1997;63:3569-3576.
    227. Koch R, Spreinat A, Lemke K, Antranikian G. Purification and properties of a hyperthermoactive a-amylase from the archaeobacterium Pyrococcus woesei. Archives of Microbiology 1991;155:572-578.
    228. Ruttersmith LD, Daniel RM. Thermostable cellobiohydrolase from the thermophilic eubacterium Thermotoga sp. strain FjSS3-B.1:Purification and properties. Biochemical Journal 1991;277:887-890.
    229. Sunna A, Puls J, Antranikian G. Purification and characterization of two thermostable endo-1,4-(3-D-xylanases from Thermotoga thermarum. Biotechnology and Applied Biochemistry 1996:24:177-185.
    230. Bauer MW, Driskill LE, Callen W, Snead MA, Mathur EJ, Kelly RM. An endoglucanase, eg1A, from the hyperthermophilic archaeon Pyrococcus furiosus hydrolyzes P-1,4 bonds in mixed-linkage (1→3),(1→4)-b-D-glucans and cellulose. Journal of Bacteriology 1999;181:284-290.
    231. Saha BC, Zeikus JG. Characterization of thermostable α-glucosidase from Clostridium thermohydrosulfuricum 39E. Applied Microbiology and Biotechnology 1991;35:568-571.
    232. Hess JM, Kelly RM. Influence of polymolecular events on inactivation behavior of xylose isomerase from Thermotoga neapolitana 5068. Biotechnology and Bioengineering 1999;62:509-517.
    233. Sriprapundh D, Vieille C, Zeikus JG. Molecular determinants of xylose isomerase thermal stability and activity:Analysis of thermozymes by site-directed mutagenesis. Protein Engineering 2000;13:259-265.
    234. Vieilee C, Hess JM, Kelly RM, Zeikus JG. xylA cloning and sequencing and biochemical characterization of xylose isomerase from Thermotoga neapolitana. Applied and Environmental Microbiology 1995;61:1867-1875.
    235. Tsujibo H, Minoura K, Miyamoto K, Endo H, Moriwaki M, Inamori Y. Purification and properties of a thermostable chitinase from Streptomyces thermoviolaceus OPC-520. Applied and Environmental Microbiology 1993;59:620-622.
    236. Ikceda M, Clark DS. Molecular cloning of extremely thermostable esterase gene from hyperthermophilic archaeon Pyrococcus furiosus in Escherichia coli. Biotechnology and Bioengineering 1998;57:624-629.
    237. Deckert G, Warren PV, Gaasterland T, Young WG, Lenox AL, Graham DE, Overbeek R, Snead MA, Keller M, Aujay M, Huber R, Feldman RA, Short JM, Olsen GJ, Swanson RV. The complete genome of the hyperthermophilic bacterium Aquifex aeolicus. Nature 1998;392:353-358.
    238. Kawarabayasi Y, Hino Y, Horikawa H, Yamazaki S, Haikawa Y, Jin-No K, Takahashi M, Sekine M, Baba SI, Ankai A, Kosugi H, Hosoyama A, Fukui S, Nagai Y, Nishijima K, Nakazawa H, Takamiya M, Masuda S, Funahashi T, Tanaka T, Kudoh Y, Yamazaki J, Kushida N, Oguchi A, Aoki KI, Kubota K, Nakamura Y, Nomura N, Sako Y, Kikuchi H. Complete genome sequence of an aerobic hyper-thermophilic crenarchaeon, Aeropyrum pernix K1. DNA Research 1999;6:83-101.
    239. Shirley BA, Stanssens P, Hahn U, Pace CN. Contribution of hydrogen bonding to the conformational stability of ribonuclease T1. Biochemistry 1992;31:725-732.
    240. Anderson DE, Becktel WJ, Dahlquist FW. PH-induced denaturation of proteins:A single salt bridge contributes 3-5 kcal/mol to the free energy of folding of T4 lysozyme. Biochemistry 1990;29:2403-2408.
    241. Pace CN. Contribution of the hydrophobic effect to globular protein stability. Journal of Molecular Biology 1992;226:29-35.
    242. Burley SK, Petsko GA. Aromatic-aromatic interaction:A mechanism of protein structure stabilization. Science 1985;229:23-28.
    243. Matsumura M, Signor G, Matthews BW. Substantial increase of protein stability by multiple disulphide bonds. Nature 1989;342:291-293.
    244. Cacciapuoti G, Porcelli M, Bertoldo C, De Rosa M, Zappia V. Purification and characterization of extremely thermophilic and thermostable 5'-methylthioadenosine phosphorylase from the archaeon Sulfolobus solfataricus. Purine nucleoside phosphorylase activity and evidence for intersubunit disulfide bonds. Journal of Biological Chemistry 1994;269:24762-24769.
    245. Wittung-Stafshede P. Role of cofactors in protein folding. Accounts of Chemical Research 2002;35:201-208.
    246. Arnold FH, Zhang J-H. Metal-mediated protein stabilization. Trends in Biotechnology 1994;12:189-192.
    247. Mateo C, Palomo JM, Fernandez-Lorente G, Guisan JM, Fernandez-Lafuente R. Improvement of enzyme activity, stability and selectivity via immobilization techniques. Enzyme and Microbial Technology 2007;40:1451-1463.
    248. Atomi H. Recent progress towards the application of hyperthermophiles and their enzymes. Current Opinion in Chemical Biology 2005;9:166-173.
    249. Jaenicke R, Bohm G. The stability of proteins in extreme environments. Current Opinion in Structural Biology 1998;8:738-748.
    250. Lazaridis T, Lee I, Karplus M. Dynamics and unfolding pathways of a hyperthermophilic and a mesophilic rubredoxin. Protein Science 1997;6:2589-2605.
    251. Matthews BW. Structural and genetic analysis of protein stability. Annual Review of Biochemistry 1993:62:139-160.
    252. Sterner R, Liebl W. Thermophilic adaptation of proteins. Critical Reviews in Biochemistry and Molecular Biology 2001;36:39-106.
    253. Vogt G, Woell S, Argos P. Protein thermal stability, hydrogen bonds, and ion pairs. Journal of Molecular Biology 1997;269:631-643.
    254. Eijsink VGH, GAseidnes S, Borchert TV, Van Den Burg B. Directed evolution of enzyme stability. Biomolecular Engineering 2005;22:21-30.
    255. Zhao H, Arnold FH. Directed evolution converts subtilisin E into a functional equivalent of thermitase. Protein Engineering 1999;12:47-53.
    256. Reetz MT, D Carballeira J, Vogel A. Iterative saturation mutagenesis on the basis of B factors as a strategy for increasing protein thermostability. Angewandte Chemie International Edition 2006;45:7745-7751.
    257. Palackal N, Brennan Y, Callen WN, Dupree P, Frey G, Goubet F, Hazlewood GP, Healey S, Kang YE, Kretz KA, Lee E, Tan X, Tomlinson GL, Verruto J, Wong VWK, Mathur EJ, Short JM, Robertson DE, Steer BA. An evolutionary route to xylanase process fitness. Protein Science 2004; 13:494-503.
    258. Malakauskas SM, Mayo SL. Design, structure and stability of a hyperthermophilic protein variant. Nature Structural Biology 1998;5:470-475.
    259. Joo JC, Pohkrel S, Pack SP, Yoo YJ. Thermostabilization of Bacillus circulans xylanase via computational design of a flexible surface cavity. Journal of Biotechnology 2010;146:31-39.
    260. Caflisch A, Karplus M. Molecular dynamics simulation of protein denaturation:Solvation of the hydrophobic cores and secondary structure of barnase. Proceedings of the National Academy of Sciences of the United States of America 1994;91:1746-1750.
    261. Daggett V, Levitt M. Protein unfolding pathways explored through molecular dynamics simulations. Journal of Molecular Biology 1993;232:600-619.
    262. Huang X, Gao D, Zhan CG. Computational design of a thermostable mutant of cocaine esterase via molecular dynamics simulations. Organic and Biomolecular Chemistry 2011;9:4138-4143.
    263. Joo JC, Pack SP, Kim YH, Yoo YJ. Thermostabilization of Bacillus circulans xylanase: Computational optimization of unstable residues based on thermal fluctuation analysis. Journal of Biotechnology 2011;151:56-65.
    264. Purmonen M, Valjakka J, Takkinen K, Laitinen T, Rouvinen J. Molecular dynamics studies on the thermostability of family 11 xylanases. Protein Engineering, Design and Selection 2007;20:551-559.
    265. Dantas G, Kuhlman B, Callender D, Wong M, Baker D. A large scale test of computational protein design:Folding and stability of nine completely redesigned globular proteins. Journal of Molecular Biology 2003;332:449-460.
    266. Nauli S, Kuhlman B, Baker D. Computer-based redesign of a protein folding pathway. Nature Structural Biology 2001;8:602-605.
    267. Kuhlman B, O'Neill JW, Kim DE, Zhang KYJ, Baker D. Accurate computer-based design of a new backbone conformation in the second turn of protein L. Journal of Molecular Biology 2002;315:471-477.
    268. Kuhlman B, O'Neill JW, Kim DE, Zhang KYJ, Baker D. Conversion of monomeric protein L to an obligate dimer by computational protein design. Proceedings of the National Academy of Sciences of the United States of America 2001;98:10687-10691.
    269. Zhang XJ, Baase WA, Matthews BW. Multiple alanine replacements within a-helix 126-134 of T4 lysozyme have independent, additive effects on both structure and stability. Protein Science 1992:1:761-776.
    270. Van Den Burg B, Vriend G, Veltman OR, Venema G, Eijsink VGH. Engineering an enzyme to resist boiling. Proceedings of the National Academy of Sciences of the United States of America 1998;95:2056-2060.
    271. Zonouzi R, Khajeh K, Monajjemi M, Ghaemi N. Role of the salt bridge between Arg176 and Glu126 in the thermal stability of the Bacillus amyloliquefaciens a-amylase (BAA). Journal of Microbiology and Biotechnology 2013;23:7-14.
    272. Janin J, Wodak S, Levitt M, Maigret B. Conformation of amino acid side-chains in proteins. Journal of Molecular Biology 1978;125:357-386.
    273. Witarto AB, Sode K. Increasing the hydrophobic interaction between terminal W-motifs enhances the stability of Salmonella typhimurium sialidase. A general strategy for the stabilization of β-propeller protein fold. Protein Engineering 2001;14:891-896.

© 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