Biochemistry of Phenazine Production in Pseudomonas aeruginosa

铜绿假单胞菌生产吩嗪的生物化学

• 批准号: 7640632
• 负责人: JAMES F PARSONS
• 金额: $ 16.74万
• 依托单位: UNIVERSITY OF MD BIOTECHNOLOGY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2010-04-24
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7640632
• 关键词: Accounting; Acquired Immunodeficiency Syndrome; Address; Alcohols; Anabolism; Anthranilate Synthase; Antibiotic Therapy; Antibiotics; Bacteria; Behavior; Biochemistry; Bioinformatics; Biological; Biological Assay; Burn injury; Catalysis; Chemicals; Chorismic Acid; Commit; Complement; Complex; Cystic Fibrosis; Data; Decarboxylation; Elements; Engineering; Enzymatic Biochemistry; Enzymes; Evaluation; Evolution; Future; Glutaminase; Glutamine; Goals; Health; Host Defense; Human; Hydroxylation; Immunity; In Vitro; Individual; Infection; Kinetics; Lead; Libraries; Ligands; Malignant Neoplasms; Methyltransferase; Nosocomial Infections; Organism; Pathway interactions; Phenazines; Pigments; Production; Property; Protein Biosynthesis; Proteins; Pseudomonas aeruginosa; Pyocyanine; Reaction; Research; Severities; Structural Biochemistry; Structure; Substrate Specificity; Therapeutic; United States; Variant; Vertebral column; Virulence Factors; Work; X-Ray Crystallography; anthranilate; antimicrobial; carboxylate; combat; design; enzyme pathway; in vivo; inhibitor/antagonist; mortality; mutant; pathogen; three dimensional structure

DESCRIPTION (provided by applicant): Phenazines are pigmented secondary metabolites produced by Pseudomonas aeruginosa. Long believed to be innocuous, phenazines are now known to have significant and deleterious biological effects on host organisms. Phenazines enhance the ability of P. aeruginosa to compete and aid the bacteria in outwitting host defenses in ways that contribute to the notoriously persistent infections caused by this organism. The long term objective of this research is to evaluate the feasibility of disabling the phenazine biosynthetic pathway and assessing whether this could be an effective strategy for controlling P. aeruginosa, most likely in combination with traditional antibiotic therapy. The overall goals of this research are to determine the chemical mechanisms of phenazine antibiotic biosynthesis through the use of structural and mechanistic studies that will fill gaps in our understanding and permit evaluation of the feasibility of developing specific inhibitors of phenazine biosynthesis. The initial tricyclic phenazine backbone is synthesized form chorismic acid by seven core enzymes, three of which (PhzD, -F, and -G) we recently examined in crystallographic and mechanistic studies. The specific aims of this project are to evaluate the enzymology and structural biochemistry of three additional enzymes. We will examine PhzE, which catalyzes the first committed step in phenazine biosynthesis, and two key phenazine modifying enzymes, PhzM and PhzS, that produce pyocyanin, a phenazine with significant bioactivity. Using X-ray crystallography, we will determine the three- dimensional structures of these proteins. Enzymology studies will focus on the substrate specificity and mechanistic properties of each enzyme that contributes to their ability to efficiently produce phenazine pathway intermediates. The results will provide a framework for future studies that will address the design of phenazine biosynthesis inhibitors and the feasibility of using them as therapeutics. The opportunistic pathogen Pseudomonas aeruginosa is a serious threat to individuals whose immunity is compromised by cystic fibrosis, burns, cancer, AIDS, and other conditions. P. aeruginosa accounts for 10 percent of nosocomial infections in the United States and mortality rates range from 20 percent to as high as 70 percent for those with the most serious underlying health problems. New strategies that complement existing antimicrobial therapies clearly need to be developed to more effectively combat P. aeruginosa infections.

描述（由申请人提供）：非那嗪是铜绿假单胞菌产生的色素次生代谢物。长期以来人们认为非那嗪是无害的，现在人们知道它对宿主生物有显著的有害生物效应。非那嗪增强了铜绿假单胞菌的竞争能力，并帮助细菌以智胜宿主防御的方式，有助于由这种生物体引起的臭名昭著的持续感染。本研究的长期目标是评估禁用非那嗪生物合成途径的可行性，并评估这是否可能是控制铜绿假单胞菌的有效策略，最有可能与传统抗生素治疗联合使用。本研究的总体目标是通过结构和机制研究来确定非那嗪抗生素生物合成的化学机制，这将填补我们理解中的空白，并允许评估开发非那嗪生物合成特异性抑制剂的可行性。最初的三环苯那嗪主链是由七种核心酶合成的，其中三种（PhzD， -F和-G）我们最近在晶体学和机制研究中进行了研究。本项目的具体目的是评价另外三种酶的酶学和结构生物化学。我们将研究PhzE，它催化了非那嗪生物合成的第一步，以及两个关键的非那嗪修饰酶，PhzM和PhzS，它们产生pyocyanin，一种具有显著生物活性的非那嗪。利用x射线晶体学，我们将确定这些蛋白质的三维结构。酶学研究将集中于底物特异性和每种酶的机制特性，这些特性有助于它们有效地产生吩那嗪途径中间体的能力。该结果将为未来的研究提供框架，以解决非那嗪生物合成抑制剂的设计和将其用作治疗药物的可行性。机会致病菌铜绿假单胞菌对因囊性纤维化、烧伤、癌症、艾滋病和其他疾病而免疫力受损的个体构成严重威胁。在美国，铜绿假单胞菌占医院感染的10%，对于那些有最严重潜在健康问题的人来说，死亡率从20%到高达70%不等。显然需要开发新的策略来补充现有的抗微生物疗法，以更有效地对抗铜绿假单胞菌感染。