XAS STUDIES OF BINUCLEAR METAL SITES IN PROTEINS OF ALKALINE PHOSPHATASE SUPERFA

碱性磷酸酶SUPERFA蛋白质中双核金属位点的XAS研究

• 批准号: 8169935
• 负责人: KEITH O HODGSON
• 金额: $ 0.03万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8169935
• 关键词: Acceleration; Accounting; Active Sites; Alkaline Phosphatase; Binding; Biochemical; Biochemistry; Biological Process; Chemicals; Cobalt; Computer Retrieval of Information on Scientific Projects Database; Coupled; Data; Electronics; Enzymes; Escherichia coli; Funding; Gene Expression; Grant; Holoenzymes; Hydrolysis; Institution; Kinetics; Metabolism; Metals; Nucleotide pyrophosphatase; Phosphorus; Play; Proteins; Reaction; Research; Research Personnel; Resolution; Resources; Role; Signal Transduction; Site; Source; Specificity; Structure; Techniques; United States National Institutes of Health; Vanadates; Zinc; analog; comparative; inhibitor/antagonist; inorganic phosphate; phosphoric diester hydrolase; research study

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Phosporyl transfer reactions play a fundamental role in a wide range of biological processes such as basic metabolism, gene expression, and cell signaling, and enzymes that catalyze reactions at phosphorus have some of the largest rate accelerations known. A significant challenge in understanding the chemistry of biological phosphoryl transfer is in defining mechanisms through which phosphoryl transfer enzymes achieve their chemical selectivity. For example, alkaline phosphatase from E. coli (AP) and nucleotide pyrophosphatase/phosphodiesterase from X. axonopodis (NPP) both catalyze hydrolysis reactions of phosphate diesters and monoesters at a structurally very similar binuclear zinc active site ligated by His and Asp residues. However, AP preferentially catalyzes monoester hydrolysis by a factor of 10^9, whereas NPP preferentially catalyzes diester hydrolysis by factors ranging from 10^2 to 10^6. It has been suggested that fine structural differences between the binuclear Zn sites of AP and NPP that are beyond the resolution of the current x-ray crystallographic structures (1.7 ? 2.0 A) may account for some of the specificity for phosphate monoesters or diesters. We will use XAS to study the binuclear active center in AP and NPP for a variety of protein forms such as holoenzyme, substrate- (phosphate monoester or diester), inhibitor- (inorganic phosphate or phosphate monoester), and transition state analog (vanadate) bound enzymes. These studies will include wild-type zinc-containing AP and NPP as well as their cobalt-substituted analogs. By applying XAS technique at the Zn, Co, and V K-edge, we will be able to provide electronic and high-resolution structural information on the metal center during the catalytic cycle. When coupled to biochemical and kinetic data, these experiments will contribute to comparative structural analysis of AP and NPP and advance our understanding of how structural features contribute to chemical selectivity of the binuclear metal site.

这个子项目是众多研究子项目之一