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：核苷酸几乎在全部起重要作用 生化过程，它们为DNA和RNA提供构建块， 充当各种代谢途径中的能量货币 酶活性的调节剂，并充当瞬态电子 受体和捐助者。该研究计划的目的是 在分子水平上理解核苷酸在总体上的作用 四种蛋白质系统的催化机制：乙酰辅酶A羧化酶 Mg（II）-ATP依赖性Kanamycin核苷酸转移酶，可以 使用ATP，GTP或UTP作为底物，UDP-Galactose 4- epimerase，该酶 需要紧密结合的NAD进行活性，L-苯基丙氨酸脱氢酶 它可逆地绑定NAD或NADH。 卡那霉素核苷酸转移酶催化各种灭活 经常用于严重治疗的氨基糖苷抗生素 由于有氧革兰氏阴性细菌引起的感染。 udp-galactose 4- 分配酶在适当的半乳糖代谢中起关键作用，实际上是 半乳糖血症的形式来自该酶的缺乏。 乙酰辅酶A。 羧酶催化了第一个也是绝对至关重要的步骤 长链脂肪酸的生物合成。 最后，L-苯基丙氨酸 脱氢酶催化L-苯基丙氨酸的氧化脱氨基。 对于拟议的研究，位置定向诱变的组合，x- 将采用射线晶体学和动力学测量。 拍摄 这些研究将共同​​提供有关作用的详细描述 这些蛋白质的酶促功能中的核苷酸。