Crystallographic Analysis of NMN Adenylytransferases

NMN 腺苷酸转移酶的晶体学分析

• 批准号: 6752498
• 负责人: HONG ZHANG
• 金额: $ 19.5万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-15 至 2006-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6752498
• 关键词: DNA binding protein; Escherichia coli; Haemophilus influenzae; Salmonella typhimurium; X ray crystallography; adenosine triphosphate; bacterial proteins; crystallization; dinucleotide; enzyme mechanism; enzyme substrate complex; gene expression; nicotinamide; nicotinamide adenine dinucleotide; nicotinamide ribotide; nucleotidyltransferase; oligonucleotides; polymerase chain reaction; protein purification; protein structure function; site directed mutagenesis

DESCRIPTION: (provided by applicant) Nicotinamide mononucleotide adenylyltransferase (NMNAT) is an indispensable enzyme in the biosynthesis and salvage of NAD and NADP in all living organisms. In prokaryotes, it is absolutely required for cell survival, thus representing an attractive target for designing new broad-spectrum anti-infectious pharmaceutics. There is also considerable medical interest in human NMNAT because it catalyzes the key step in the metabolic conversion of the antitumor drug tiazofurin to its active form, tiazofurin adenine dinucleotide (TAD). Because of the vital roles of NAD in the cell, adequate levels of NAD must be maintained. In bacteria, a single protein NadR performs multiple functions in response to the cellular NAD and ATP levels. These include a transcriptional repressor, a NMN adenlyltransferase, and a nicotinamide ribose kinase. NadR regulates the expression of the genes involved in both de novo biosynthesis and savage of NAD. It also controls the uptake of NMN and its subsequent adenylation. Structural information of NMNAT and NadR, along with their complexes with substrates will be essential for understanding the catalysis, substrate recognition, inhibition, as well as regulation of these important enzymes. We have solved the crystal structure of the first bacterial NMNAT in its ligand free form and have obtained well diffracting human NMNAT crystals. Comparison of the bacterial and human enzyme structures will help to design specific bacterial inhibitors with high selectivity. Additionally, we have expressed and purified NadR proteins from S. typhimurium and H. influenzae, and the crystallization trials are in progress. Elucidating the structures of NadR in its various ligand-bound forms and its complex with DNA will reveal how its conformation and function are modulated by both NAD and ATP.

说明：（由申请人提供）烟酰胺单核苷酸