STRUCTURAL STUDIES OF NUCLEOTIDE DEPENDENT ENZYMES

核苷酸依赖性酶的结构研究

• 批准号: 2561100
• 负责人: Hazel M. Holden
• 金额: $ 22.21万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-06-01 至 2002-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2561100
• 关键词: X ray crystallography; acetyl coA carboxylase; adenosine triphosphate; aminoacid oxidase; biotin; chemical kinetics; enzyme mechanism; enzyme structure; galactose; guanosine triphosphate; isomerase; kanamycin; magnesium ion; nicotinamide adenine dinucleotide; nucleotides; nucleotidyltransferase; phenylalanine; site directed mutagenesis; structural biology; uridine diphosphate; uridine triphosphate

DESCRIPTION: Nucleotides serve important roles in virtually all biochemical processes where they provide building blocks for DNA and RNA, act as currencies of energy in various metabolic pathways, serve as modulators of enzymatic activity, and function as transient electron acceptors and donors. The objective of this research program is to understand, on a molecular level, the role of nucleotides in the overall catalytic mechanisms of four protein systems: acetyl-CoA carboxylase which is Mg(II)-ATP dependent, kanamycin nucleotidyltransferase which can employ ATP, GTP, or UTP as a substrate, UDP-galactose 4-epimerase which requires tightly bound NAD for activity, and L-phenylalanine dehydrogenase which binds NAD or NADH reversibly. Kanamycin nucleotidyltransferase catalyzes the inactivation of various aminoglycoside antibiotics often employed in the treatment of serious infections due to aerobic Gram-negative bacteria. UDP-galactose 4- epimerase plays a key role in proper galactose metabolism, and indeed, one form of galactosemia arises from a deficiency in this enzyme. Acetyl-CoA carboxylase catalyses the first and absolutely critical step in the biosynthesis of long chain fatty acids. Finally, L-phenylalanine dehydrogenase catalyzes the oxidative deamination of L-phenylalanine. For the proposed studies, a combination of site-directed mutagenesis, x- ray crystallography, and kinetic measurements will be employed. Taken together, these studies will provide a detailed description of the role of nucleotides in the enzymatic functions of these proteins.

描述：核苷酸在几乎所有领域都发挥着重要作用。 它们为 DNA 和 RNA 提供构建模块的生化过程， 在各种代谢途径中充当能量货币， 酶活性调节剂，并充当瞬态电子 接受者和捐赠者。该研究计划的目标是 在分子水平上了解核苷酸在整体中的作用 四种蛋白质系统的催化机制：乙酰辅酶A羧化酶 这是 Mg(II)-ATP 依赖性卡那霉素核苷酸转移酶，可以 采用 ATP、GTP 或 UTP 作为底物，UDP-半乳糖 4-差向异构酶 需要紧密结合的 NAD 才能发挥活性，而 L-苯丙氨酸脱氢酶 它可逆地结合 NAD 或 NADH。 卡那霉素核苷酸转移酶催化多种失活 氨基糖苷类抗生素常用于治疗严重的 由需氧革兰氏阴性菌引起的感染。 UDP-半乳糖4- 差向异构酶在适当的半乳糖代谢中起着关键作用，事实上，一种 半乳糖血症的一种形式是由于这种酶的缺乏而引起的。 乙酰辅酶A 羧化酶催化第一步也是绝对关键的步骤 长链脂肪酸的生物合成。 最后，L-苯丙氨酸 脱氢酶催化L-苯丙氨酸的氧化脱氨。 对于拟议的研究，结合了定点诱变、x- 将采用射线晶体学和动力学测量。 采取 这些研究将共同​​详细描述 这些蛋白质的酶促功能中的核苷酸。