Structure-function analyses of siderophore biosynthetic enzymes

说明(申请人提供)：铁载体是由细菌产生的低分子铁络合剂，用于从环境中清除铁，通常是细菌毒力所必需的。该实验室研究的长期目标是提供对铁载体生物合成途径中的酶的详细机制和结构的了解，这些途径是药物发现的目标。为此，我们建议研究非核糖体多肽合成酶辅助酶，这些酶参与了从铜绿假单胞菌中产生铁载体蛋白绿素和焦蛋白的过程。在将要研究的四种酶中，有两种是理想的模型体系，即异分枝酸合成酶(PchA)和异分枝酸-丙酮酸裂解酶(PchB)，它们可以在理解催化的替代反应途径方面取得根本性进展。鸟氨酸羟基酶(PvdA)的研究为新的黄素生物化学显示了希望，并首次提出了羟基鸟氨酸转换酶(PVDF)的性质。我们将使用包括酶动力学分析、结构生物学和计算酶学在内的多方面方法。 铜绿假单胞菌是一种危险的病原体，是易感宿主感染的常见原因，包括癌症和艾滋病患者、免疫缺陷患者、囊性纤维化患者、烧伤患者和包括婴儿在内的其他高危个人。这项工作的目标是提供对促进铜绿假单胞菌毒力的四种酶的基本了解，以便利用这些信息来生产新的抗微生物药物。

DESCRIPTION (provided by applicant): Siderophores are low molecular weight iron chelators produced by bacteria to scavenge iron from the environment, and are frequently required for bacterial virulence. The long-term goal of the research in this laboratory is to provide a detailed mechanistic and structural understanding of enzymes in the siderophore biosynthetic pathways that are targets for drug discovery. Toward that end, we propose to investigate the nonribosomal peptide synthetase accessory enzymes that are involved in the production of the siderophores pyochelin and pyoverdin from the bacteria P. aeruginosa. Two of the four enzymes to be studied, the isochorismate synthase (PchA) and isochorismate-pyruvate lyase (PchB), are ideal model systems for making fundamental advances in understanding alternate reaction pathways for catalysis. The studies of the ornithine hydroxylase (PvdA) show promise for novel flavin biochemistry, and the first characterization of the hydroxyornithine transformylase (PvdF) is proposed. We will use a multifaceted approach that includes enzyme kinetic analysis, structural biology and computational enzymology. Narrative Pseudomonas aeruginosa is a dangerous pathogen that is a common cause of infections in susceptible hosts, including cancer and AIDS patients, those with immune deficiencies, cystic fibrosis patients, burn patients and other at risk individuals including infants. The goal of this work is to provide a fundamental understanding of four enzymes that promote virulence in P. aeruginosa so that this information can be exploited to generate new antimicrobial drugs.