重组肺炎链球菌HMGR特性分析及抑制剂筛选
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
肺炎链球菌(Streptoccus pneumoniae)是引起脑膜炎、菌血症、肺炎等疾病的主要致病菌,近年来由于环境污染和抗生素的乱用而造成多药抗性的肺炎链球菌菌株逐年增加,对抗生素的抗性逐年增强。HMG-CoA还原酶(HMG-CoA reductase,HMGR)是甲羟戊酸(mevalonate)途径的限速酶,催化HMG-CoA还原为甲羟戊酸。本研究从肺炎链球菌基因组DNA中PCR扩增出mvaA基因全长1275bp的完整编码序列,将其克隆到pMD18-T载体中,转化大肠杆菌DH5α。重组质粒经HindⅢ和BamHI双酶切分析并测序证实的阳性重组子亚克隆到pET-28a(+)表达载体中,转化大肠杆菌BL21(DE3)。在30℃以1mM IPTG诱导表达,Ni-NTA层析柱分离纯化后经SDS-PAGE分析表明在约47kD处有特异性表达带。肺炎链球菌HMGR以NADPH作为辅酶,动力学分析采用紫外分光光度法检测NADPH在340nm处吸收值的变化。检测结果表明肺炎链球菌HMGR的最适pH约为6.5,最适温度37℃。粗酶提取物的比活为11.22U/mg,分离纯化后比活为31.98U/mg,比活提高2.8倍。在37℃,pH6.5时的Vmax和Km分别为62.1U/mg和260μM。罗伐他汀是HMGR的竞争性抑制剂,对肺炎链球菌HMGR的抑制常数Ki为362μM。表达纯化后的重组HMGR免疫新西兰大白兔,提取抗血清,ELISA检测其效价为1:320000,Western杂交证明HMGR具有特异性杂交条带。
     序列分析表明,HMGR主要存在两类,Ⅰ类主要存在于真核生物和部分古细菌中,Ⅱ类主要存在于原核生物和部分古细菌中。他汀类药物是Ⅰ类HMGR的良好竞争性抑制剂,其Ki常数在nM范围内,但是他汀类药物对Ⅱ类HMGR的抑制效果并不明显,其Ki值在μM范围内。为了寻找更专一有效的针对Ⅱ类HMGR的竞争性抑制剂,本文以假单孢杆菌HMGR晶体结构为模板,通过SYBYL7.0软件,用同源模建的方法分析了肺炎链球菌HMGR的三维结构,根据其同源模建和三维结构筛选HMGR的竞争性抑制剂。用重组表达的肺炎链球菌HMGR,检测筛选到的抑制剂的抑制效果。初步分析结果表明,在待筛选的30种化合物中,筛选到一种比传统的竞争性抑制剂罗伐他汀具有更佳抑制效果的化合物,其抑制常数Ki约为76μM,此种化合物可作为进一步研究新型抗菌药物的预选药物。目前,以计算机分析三维结构为手段,用同源模建的方法寻找结构类似物来研究新药的开发是一种有效的途径,本实验为进一步寻找专一性的特效抑制剂奠定了基础。
Streptococcus pneumoniae is the major causative organisms of meningitis, bacteremia,and pneumonia.Resently,for the Environmental pollution the excess use of antibiotics,the drug resistance of S.pneumoniae to antibiotics showed ascending tendency.Hydroxymethylglutaryl-coenzyme A reductase(HMGR) is the rate-limiting enzyme in the classical mevalonate pathway,which converts HMG-CoA to mevalonate, the rate-limiting step in isopentenyl diphosphate(IPP) biosynthisis.The present study cloned the full-length HMG-CoA reductase(HMGR) gene of S.pneumoniae,and expressed in E.coli BL21(DE3).The recombinant protein was purified by Ni-NTA affinity chromatography and obtained the high activity HMGR.Activity was optimal at pH6.5 and approximately 37℃The specific activity of the crude extract and the Ni~(2+) -NTA were 11.22 U/mg and 31.48 U/mg respectively.The enzyme catalyzes the normal anabolic reaction using NADPH not NADU as a reductant,the V_(max)and K_m of the reductive deacylation of HMG-CoA to mevalonate were 62.1U/mg and 260μM respectively.Lovastatin inhibited competitively with HMG-CoA with the K_i362μM. New Zealand rabbits were immunized with the purify HMGR protein.The antiserum was detected by ELISA and the titer of these antibodies was up to 1:320,000.The specificity of these antibodies against HMGR was further confirmed by western blotting.
     Comparison of the sequence of HMGR has revealed the existence of two classes of this enzyme,the classⅠenzymes found in eukaryotes and some archaea,and the classⅡfound in certain eubacteria and the archaea.Statins represent a kind of excellent competing inhibitor targeted for the classⅠHMGR,but were relatively poor to the classⅡenzyme of important bacterial pathogens.Potent HMGR inhibitors with Ki values in the nM range to the classⅠenzyme,but in theμM range to the classⅡenzyme,it is high 10~3-10~5 folders.In order to develop new inhibitors with more specific and stronger function targeted for the classⅡHMGR,the 3D model of S.pneumoniae HMGR was built based on structure template of HMGR of Pseudomonas mevalonii by homology modeling using composer module of SYBYL7.0 program.Acoding to the homology modeling of S.pneumoniae,we screen out one better inhibitor with the ki of 76μM from 30 kinds of inhibitors.Currently,using computer to analyze three-dimensional structure and using homology modeling to search for structural analogues and then develop new drugs is a new research area.
引文
1.曹炬,尹一兵.肺炎链球蛋白质疫苗研究进展.国际检验医学杂志.2007,28(3):214-216.
    2.陈保德,尹一兵.肺炎链球菌致病的分子机理.国外医学临床生物化学与检验学分册.2002,23(6):362-364.
    3.胡晓彦,桂炳东.肺炎链球菌分子流行病学研究进展.江西医学检验.2007,25(5):499-490.
    4.刘晓红.肺炎链球菌感染及耐药机制研究新进展.医学检验与临床.2007,18(1):56-58.
    5.刘晓红,张绪利.肿炎链球菌耐药性分析.世界健康杂志.2007,3(4):74-75.
    6.刘亚昆.武汉地区肺炎链球菌的红霉素耐药性分析及血清分型研究.2006,8(3):4-9.
    7.李南,王非,胥文春等.肺炎链球菌双组份系统中组氨酸激酶(YycG)的同源模建与分析.生物工程学报.2009,25(2):207-214.
    8.李南,王非,牛司强等.组氨酸激酶(Yyc G)在筛选肺炎链球菌抑制剂中的应用.中国生物工程杂志.2009,29(3):25-29.
    9.吴金英,李少君,徐新波等.肺炎链球菌对大环内酯类抗菌药物耐药机制的研究.中华医院感染学杂志.2008,18(12):1681-1683.
    10.孙爱华,樊欢,夏肖萍等.肺炎链球菌ciaH/R基因重组表达及C iaH/R与β-内酰胺类耐药相关性.浙江大学学报(医学版).2008,37(6):605-611.
    11.胥文春,曹炬,许颂霄等.肺炎链球菌毒力因子PspA的原核表达、纯化及鉴定.重庆医科大学学报.2007,32(6):571-574.
    12.胥文春,赵清,孟江萍等.以gfp为报告基因的肺炎链球菌启动子诱捕文库的构建与分析.微生物学通报.2008,35(12):1992-1998.
    13.杨银梅,叶惠芬,钟丽嫦等.肺炎链球菌对泰利霉素等抗菌药物的体外抗菌活性.中国感染与化疗杂志.2008,8(2):146-147.
    14.袁竹青,吴忠道,余新炳等.肺炎链球菌不同菌株自溶酶基因的克隆、序列分析及重组表达.中华传染病杂志.2005,23(2):87-90.
    15.袁丽萍,马利敏,赵学增等.肺炎链球菌耐药性研究及治疗进展.中国药师.2006,9(4):367-369.
    16.张群,尹楠林,胥文春等.clpE基因缺失对肺炎链球菌毒力的影响.微生物学报. 2009,49(2):233-238.
    17.张泓,吴文娟,倪语星.多重耐药肺炎链球菌研究进展及防治策略.中国感染与化疗杂志.2007,7(2):138-140.
    18.张泓,吴文娟,李万华等.肺炎链球菌对大环内酯类抗生素耐药机制研究.中国感染与化疗杂志.2008,8(1):15-19.
    19.张在亭,刘思梅,刘岚.肺炎链球菌耐药趋势及耐药机制研究进展.国际儿科学杂志.2007,34(1):40-42.
    20.赵晓姬,张素芬,潘淑等.216例葡萄球菌感染分布及耐药性分析.国际检验医学杂志,2007,28(12):1091-1093.
    21.赵清,李南,张雪梅等.肺炎链球菌转化模型的建立.第四军医大学学报.2008,29(9):804-806.
    22.J.萨姆布鲁克,D.W.拉塞尔著.黄培堂等译.分子克隆实验指南(第三版),科学出版社,2002.
    23.http://baike.baidu.com/view/724689.htm.
    24.Berendsen HJC,Postma JPM,Gunsteren WF van,et al.Molecular dynamics with coupling to an external bath[J].J.Comput.Phys.,1984,81:3684-3690.
    25.Bischoff KM,Rodwell VW.3-hydroxy-3-methylglutaryl coenzyme-A reductase from Haloferax volcanii:purification,characterization,and expression in Escherichia coli[J].J Bacteriol,1996,178(1):19-23.
    26.Bohm M,Hjalmarson A,Kjekshus J,et al.Heart failure and statins-Why do we need a clinical trial[J].Z Kardiol,2005,94:223-230.
    27.Bochar DA,Stauffacher C V,Rodwell V W.Sequence comparisons reveal two classes of 3-hydroxy-3-methylglutaryl coenzyme A reductase[J].Mol Genet Metab,1999,66:122-127.
    28.Boucher Y,Huber H,Haridon S L,et al.Bacterial origin for the isoprenoid biosynthesis enzyme HMG-CoA reductase of the archaeal orders thermoplasmatales and archaeoglobales[J].Mol.Biol.Evol,2001,18(7):1378-1388.
    29.Case DA,Pearlman,JW,Caldwell TE,et al.AMBER 8.University of California:San Francisco,CA.,2002.
    30.Darden T,York D and Pedersen L.Particle mesh Ewald--an Nlog(N) method for Ewald sums in large systems[J].J.Chem.Phys.,1993,98:10089-10092.
    31.Essmann U,Perera L,Berkowitz ML,et al.A smooth particle mesh Ewald method [J].J.Chem.Phys,1995,103:8577-8593.
    32.Friesen JA.,and V.W.Rodwell.The 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductases[J].Genome Bio,2004,5:248.
    33. Frimpong K and Rodwell V W. Catalysis by Syrian Hamster 3-Hydroxy-3-methylglutaryl-coenzyme A Reductase [J]. JBC, 1994, 269(15): 11478-11483.
    34. Garenne, M., C. Rosmans, and H. Campbell. 1995. The magnitude of mortality from acute respiratory infections in children under 5 year in developing countries [J]. World Health Stat. 46: 180-191.
    35. Garenne M, Rosmans C, Campbell H. The magnitude of mortality from acute respiratory infections in children under 5 year in developing countries [J]. World Health Stat, 1995,46: 180-191.
    36. Guerrrero RH, Diaz JP, Montalvetti A, et al. Kinetic properties and inhibition of Trypanosoma cruzi 3-hydroxy-3-methylglutaryl CoA reductase [J]. FEBS Lett, 2002, 510: 141-4.
    37. Hedl M, Tabernero L, Stauffacher C V, et al. Class Ⅱ 3-hydroxy-3-methylglutaryl coenzyme-A reductases [J]. J Baeteriol, 2004, 186 (7): 1927-1932.
    38. Janet L, Colli, M.D, Christopher L, et al. High cholesterol levels are associated with reduced prostate cancer mortality rates during periods of high but not low statin use in the United States [J]. Urologic Oncol, 2008.
    39. Jian W, Qingye Z, Ruihua L, et al. 3D-QSAR study of statin inhibitors of HMG-CoA reductase [J]. J CCNU (Nta. Sci.), 2005, 39 (4): 487-489.
    40. Jorgensen WL, Chandrasekhar J, Madura JD, et al. Comparison of Simple Potential Functions for Simulating Liquid Water [J]. J. Chem. Phys., 1983, 79: 926-935.
    41. Kim D Y, Ryu S Y, Lim J E, et al. Anti-inflammatory mechanism of simvastatin in mouse allergic asthma model [J]. Eur J Pharmacol, 2007, 557: 76-86.
    42. Kim D Y, Stauffacher C V, Rodwell V W. Dual coenzyme specificity of Archaeoglobus fulgidus HMG-CoA reductase [J]. Protein Science, 2000, 9:1226-1234.
    43. Laule O, Furholz A, Chang HS, et al. Crosstalk between cytosolic and plastidial pathways of isoprenoid biosynthesis in Arabidopsis thaliana [J]. Proc Natl Acad Sci USA, 2003, 100: 6866-6871.
    44. Laskowski RA, MacArthur MW, Moss, DS, et al. PROCHECK: A program to check the stereochemical quality of protein structures [J]. J. Appl. Crystallogr, 1993, 26: 283-291.
    45. Marz W, Wieland H. HMG-CoA Reductase Inhibition: Anti-inflammatory Effects beyond Lipid Lowering? [J]. 2000, Herz, 25:117-125.
    46. Pai R, Gertz RE, Beall B. Sequential multiplex PCR approach for determing capsular serotypes of streptococcus pneumoniae isolates [J]. J Clin Microbiol, 2006, 44, 124-131.
    47. Paraskevas K I. Applications of statins in cardiothoracic surgery: more than just lipid-lowering [J]. Eur J Cardio-thoracic Surg, 2008, 33: 377-390.
    48. Powell MJD. Restart procedures for the conjugate gradient method. Mathem. Program, 1977, 12: 241-254.
    49. Qing Y. Zhang, Kai Liu, Guzhen Cui, et al. Interactions of Ligands with Class-Ⅱ HMG-CoA Reductase of Streptococcus Pneumoniae by Homology Modeling and Molecular Dynamic Simulations [J]. J Comput Theor Nanosci, 2007, 4: 1351-1357.
    50. Rodriguez-Concepcion M, Boronat A. Elucidation of the methylerythritol phosphate pathway for isoprenoid biosynthesis in bacteria and plastids. A metabolic milestone achieved through genomics [J]. Plant Physiol, 2002, 130: 1079-1089.
    51. Robert A. The pneumococcus at the millemium: not down, not out [J]. J Infect Dis, 1999, 179(suppl2): 5338-5341.
    52. Rullmann JAC. AQUA, Computer Program. Department of NMR Spectroscopy,Bijvoet Center for Biomolecular Research, Utrecht University, The Netherlands. 1996. Ryckaert JP, Ciccotti G, Berendsen HJC. Numerical intergration of the Cartesianequations of motion of a system with constraints: Molecular synamics of n-alkanes [J]. J. Comput. Phys., 1977, 23: 327-341.
    53. Sagui C and Dardeh TA. P3M and PME: a comparison of the two methods. Simulation and Theory of Electrostatic Interactions in Solution [J]. American Institute of Physics, 1999,492: 104-113.
    54. Shurong W, Yu C, Liping W, et al. Development of predictive quantitative retention activity relationship models of HMG-CoA reductase inhibitors by biopartitioning micellar chromatography [J]. J Pharm and Biom Anal, 2008, 46: 243-249.
    55. Syka J, Ouda L, Nachtigal P, et al. Atorvastatin slows down the deterioration of inner ear function with age in mice [J]. Neurosci Lett, 2007, 411: 112-116.
    56. Tabernero L, Bochar DA, Rodwell VW, et al. Substrate-induced closure of the flap domain in the ternary complex structures provides insights into the mechanism of catalysis by 3-hydroxy-3-methylglutaryl-CoA reductase [J]. Proc. Natl.Acad.Sci. USA. 1999,96:7167-7171.
    57. Tabernero L, Rodwell V W, Stauffacher C V. Crystal structrue of a statin bound to a class Ⅱ Hydroxymethylglutaryl-CoA Reductase [J]. J Biochem, 2003, 278 (22):19933-19938.
    58. Tabernero L, Rodwell VW, Stauffacher CV. Crystal structrue of a statin bound to a class Ⅱ Hydroxymethylglutaryl-CoA Reductase [J]. J. Biochem, 2003, 278 (22): 19933-19938.
    59. Theivagt AE, Amanti EN, Beresford NJ, et al. Characterization of an HMG-CoA reductase from Listeria monocytogenes that exhibits dual coenzyme specificity [J]. J Biochem, 2006, 45:14397-06.
    60. Tousoulis D, Charakida M, Stefanadi E, et al. Statins in heart failure. Beyond the lipid lowering effect [J]. Int J Cardiol, 2007, 115: 144-150.
    61. Vrtovec B, Okrajsek R, Golicnik A, et al. Atorvastatin Therapy May Reduce the Incidence of Sudden Cardiac Death in Patients With Advanced Chronic Heart Failure [J]. J Cardiac Failure, 2008, 14: (2), 140-144.
    62. Wilding EI, Kim DY, Bryant AP, et al. Essentiality, expression, and characterization of the class Ⅱ 3-hydroxy-3-methylglutaryl-coenzyme-A reductases of Staphylococcus aureus [J]. J Bacteriol, 2000, 182(18): 5147-5152.
    63. Wilding E I, Brown J R, Bryant A P, et al. Identification, Evolution, and Essentiality of the Mevalonate Pathway for Isopentenyl Diphosphate Biosynthesis in Gram-Positive Cocci [JJ. J Bacteriol, 2000, 182 (15): 4319-4327.
    64. Wang Y L, Darnay B G, Rodwell V W. Identification of the Principal Catalytically Important Acidic Residue of 3-Hydroxy-3-methylglutaryl Coenzyme-A Reductases [J]. JBC, 1990, 265(35):21634-21641.
    65. Zhou Y, MacKinnon R. The occupancy of ions in the K~+ selectivity filter: Charge balance and coupling of ion binding to a protein conformational change underlie high conduction rates [J]. J. Mol. Biol., 2003, 333: 965-975.

© 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