Molecular Targets in Peptidoglycan Synthesis

肽聚糖合成中的分子靶标

基本信息

批准号：
7575757
负责人：
Christopher Davies
金额：
$ 29.2万
依托单位：
MEDICAL UNIVERSITY OF SOUTH CAROLINA
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-02-01 至 2011-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7575757
关键词：
Acylation Address Amidohydrolases Amino Acids Anabolism Antibiotic Resistance Antibiotic Therapy Antibiotics Autolysin Bacteria Bambermycins Biochemical Biology Boronic Acids Cefixime Ceftriaxone Cell Wall Cell division Cells Cephalosporins Ciprofloxacin Complex Development Disease Drug Delivery Systems Drug Design Enzymes Escherichia coli Generations Genetic Goals Gonorrhea Infection Intermediate resistance Lactams Lytic Mediating Metabolism Molecular Molecular Target Monobactams Multienzyme Complexes Multiprotein Complexes Mutation Neisseria gonorrhoeae Organism Penicillin-Binding Proteins Penicillins Peptides Peptidoglycan Peptidyltransferase Pharmaceutical Preparations Polysaccharides Proteins Public Health Research Personnel Resistance Role Scaffolding Protein Sexually Transmitted Diseases Structure Tetracyclines Therapeutic Agents Variant X-Ray Crystallography amidase antimicrobial base combat crosslink drug development drug discovery enzyme mechanism fluoroquinolone resistance glycosyltransferase improved insight mimetics mutant novel pathogenic bacteria polymerization programs resistant strain

项目摘要

Beta-lactam antibiotics, which target the essential transpeptidases (penicillin-binding proteins or PBPs) that cross-link peptidoglycan strands, are important drugs in the treatment of bacterial diseases. Unfortunately, the emergence of antibiotic-resistant pathogenic bacteria is a growing problem and threatens to make these and other antibiotics obsolete. Penicillin and tetracycline are no longer used to treat gonococcal infections due to the emergence of resistant strains of N. gonorrhoeae. Moreover, resistance to fluoroquinolones and third-generation cephalosporins, the two classes of antibiotics current recommended in the treatment of gonorrhea, is increasing. Clearly there is an urgent need to develop new antimicrobials directed both against well-known molecular targets, such as PBPs, but also against novel targets such as transglycosylases (TGases), which catalyze the polymerization of glycan stands, and autolysins, which break down peptidoglycan during biosynthesis. Development of new antibiotics, however, has been hindered by a dearth of mechanistic information for these enzymes. In this proposal we describe genetic, biochemical and structural studies of three classes of enzyme involved in peptidoglycan metabolism in N. gonorrhoeae. Each has been selected to address one or more of the following aims: (a) to understand the biology of peptidoglycan synthesis, (b) to explore their interactions with antibiotics, (c) to elucidate the molecular basis for antibiotic resistance and (d) to examine their potential as targets for drug development. The molecular basis for antibiotic resistance will be investigated by structural and biochemical studies of a unique variant of PBP 2 from strains of N. gonorrhoeae with intermediate-level resistance to ceftriaxone. The role of the lytic TGase MltA as part of a multienzyme complex involved in cell division will be investigated by genetic studies. The suitability of the amidase AmiC as a novel target for antimicrobials will be examined both genetically and by solving its crystal structure. Finally, the crystal structure of a TGase domain will reveal the catalytic mechanism of these enzymes and pave the way for drug design. Together, these studies will provide insight into the functional roles of these proteins in peptidoglycan metabolism but also the essential molecular information needed to bolster the current repertoire of antimicrobials directed against pathogenic bacteria. The sexually transmitted disease gonorrhea is a growing public-health problem due to the emergence of strains harboring resistance to antibiotics such as penicillin. The development of new treatments for gonococcal disease requires detailed, three-dimensional pictures of essential proteins in these bacteria for use in drug discovery. This project will use X-ray crystallography to provide such information for a number of key proteins in N. gonorrhoeae that are involved in cell wall synthesis.

靶标的转交肽酶（青霉素结合蛋白或PBP）是交叉肽聚糖链的β-内酰胺抗生素是治疗细菌疾病的重要药物。不幸的是，抗生素抗生素的致病细菌的出现是一个日益严重的问题，并有可能使这些和其他抗生素过时。青霉素和四环素不再用于治疗淋病链球菌的抗性菌株，治疗淋球菌感染。此外，对氟喹诺酮类和第三代头孢菌素的耐药性是淋病治疗中建议的两类抗生素当前的耐药性。显然，迫切需要开发针对众所周知的分子靶标（例如PBP）的新抗菌剂，也需要针对新型靶标，例如诸如克糖基酶（TGases）（TGases），这些靶标会在生物合成过程中分解肽聚糖。然而，新抗生素的开发受到这些酶缺乏的机械信息的阻碍。在这一建议中，我们描述了三类在淋病链球菌的代谢中涉及三类酶的遗传，生化和结构研究。已经选择了每个或多种目的：（a）了解肽聚糖合成的生物学，（b）探索它们与抗生素的相互作用，（c），以阐明抗生素耐药性和（d）的分子基础，以检查其作为药物开发的潜在目标。抗生素耐药性的分子基础将通过对淋病链球菌菌株的独特变体的结构和生化研究研究，具有中等水平对头孢曲松的抗性。遗传研究将研究裂解TGase MLTA作为细胞分裂涉及的多酶复合物的一部分的作用。 amidase Amic作为抗菌剂的新靶标的适合性将通过遗传和求解其晶体结构进行检查。最后，TGase结构域的晶体结构将揭示这些酶的催化机理，并为药物设计铺平道路。总之，这些研究将洞悉这些蛋白在肽聚糖代谢中的功能作用，以及加强针对致病细菌的抗菌剂的当前库所需的基本分子信息。性传播疾病淋病是一个日益增长的公共卫生问题，因为出现了对抗生素（例如青霉素）抗药性的菌株。开发针对淋球菌疾病的新疗法需要这些细菌中必需蛋白质的详细三维图片，以用于药物发现。该项目将使用X射线晶体学来为细胞壁合成中涉及的许多关键蛋白提供此类信息。