STRUCTURE AND MECHANISM OF PLP-DEPENDENT ENZYMES

PLP依赖性酶的结构和机制

• 批准号: 2291589
• 负责人: ROBERT STEPHEN PHILLIPS
• 金额: $ 2.42万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-09-01 至 1997-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2291589
• 关键词: Enterobacteriaceae; Escherichia coli; Pseudomonas; X ray crystallography; aminoacid metabolism; carbon carbon lyase; chemical kinetics; enzyme mechanism; enzyme structure; enzyme substrate; hydrolase; kynurenine; phenols; pyridoxal phosphate; site directed mutagenesis; tryptophanase; tyrosine

Pyridoxal-5'-phosphate (PLP) is the cofactor for a large number of enzymes performing a wide range of biological transformations of amino acids and amines, including transaminations, decarboxylations, and beta- and gamma- eliminations. PLP is capable of performing many of these reactions in the absence of an apoprotein matrix at much lower rates and without regiospecificity and stereospecificity. The goal of our proposed research is to determine the molecular details of the reactions of three PLP- dependent enzymes: l) Tryptophan indole-lyase from E. coli; 2) Tyrosine phenol-lyase from Citrobacter; and 3) Kynureninase from Pseudomonas fluorescens. We are especially interested in studying the role of the protein matrix in providing for the substrate and reaction specificity for these enzymes. These studies will utilize X-ray crystallographic structure determinations, rapid-reaction kinetics measurements, and site-directed mutagenesis of the enzymes.

5'-磷酸吡哆醛 (PLP) 是多种酶的辅助因子 对氨基酸进行广泛的生物转化 胺，包括转氨作用、脱羧作用以及β-和γ- 消除。 PLP 能够在 脱辅基蛋白基质的缺失率要低得多并且没有 区域特异性和立体特异性。我们提出的研究目标 是为了确定三种PLP-反应的分子细节 依赖性酶：l)来自大肠杆菌的色氨酸吲哚裂解酶； 2) 酪氨酸 来自柠檬酸杆菌的苯酚裂解酶； 3) 来自假单胞菌的犬尿氨酸酶 荧光。我们特别感兴趣的是研究 蛋白质基质提供底物和反应特异性 这些酶。这些研究将利用 X 射线晶体结构 测定、快速反应动力学测量和定点 酶的诱变。