MECHANISM OF E. COLI PYRUVATE DEHYDROGENASE COMPLEX-E1

大肠杆菌丙酮酸脱氢酶复合物-E1的作用机制

• 批准号: 6628939
• 负责人: FRANK JORDAN
• 金额: $ 34.37万
• 依托单位: RUTGERS THE STATE UNIV OF NJ NEWARK
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-02-01 至 2005-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6628939
• 关键词: X ray crystallography; enzyme activity; enzyme complex; enzyme induction /repression; enzyme inhibitors; enzyme mechanism; enzyme structure; enzyme substrate analog; isozymes; microorganism metabolism; monoclonal antibody; protein structure function; pyruvate dehydrogenase; site directed mutagenesis; thiamine

DESCRIPTION (adapted from applicant's abstract): The overall objective of this research is to enhance our understanding of structure-function relationships, including the mechanism and regulation of the El component of the pyruvate dehydrogenase multienzyme complex isolated from E. coli. This enzyme requires thiamin diphosphate (the vitamin B coenzyme) and decarboxylates pyruvate, the product of glycolysis, to initiate a series of reactions, a major product being acetyl-Coenzyme A, the starting material for the citric acid cycle. Among the specific goals for the requested period are: (1) Production of wild-type and variant El enzymes (the variants being made by site directed mutagenesis of the plasmid specifically bearing only the gene coding for El) for both mechanistic and structural studies, including, determination of the X-ray structure in a collaboration wit William Furey, University of Pittsburgh (with whom the principal investigator has collaborated in the solution of the simpler yeast pyruvate decarboxylase structure); (2) Experiments designed to a. identify the amino acids responsible for catalysis, and assign the function in catalysis; b. study the fate of key thiamin-bound intermediates on the enzyme; c. study the rate-limiting steps in catalysis and the structure of transition states in wild-type and active center variant enzymes; d. identify the site of, and solve the mechanism of inactivation of El by substrate fluoropyruvate, 2-oxo-3-butynoic acid (a potent substrate analog inhibitor developed in the principal investigator's laboratory), a putative transition-state analog, and several highly inhibitory monoclonal antibodies (also developed in the principal investigator's laboratory); (3) Experiments to identify the site(s) at which a variety of metabolic regulators interact with the El, including the cofactors and the products of the reaction, as well as GTP- and the pathway by which the information i transmitted to the active center; and (4) Explore the principal investigator's hypothesis concerning the key reductive acetyl transfer between the El and E2 enzymes. Since this enzyme is at a key metabolic junction, the principal investigator believes that in the coming years he and his collaborators have an opportunity to contribute to a better molecular-level understanding of this member of a very large class of related multienzyme complexes.

描述（改编自申请人摘要）：本研究的总体目标