Metal Cluster Active Sites in Proteins

蛋白质中的金属簇活性位点

• 批准号: 9104669
• 负责人: Lawrence Que
• 金额: $ 30.01万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-09-01 至 1995-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9104669&HistoricalAwards=false
• 关键词: Metal; Cluster; Active; Sites; Proteins

Proteins with active sites consisting of di-iron centers bridged by oxo or hydroxo groups comprise a new subclass of metalloproteins. This class includes proteins that perform a variety of functions in biology -- dioxygen transport (hemerythrin), oxygen activation (methane monooxygenase), the conversion of ribonucleotides to deoxyribonucleotide (ribonucleotide reductase), and phosphate ester hydrolysis (purple acid phosphatases). This project will focus on the latter two enzymes. Ribonucleotide reductase is the key enzyme in the biosynthesis of deoxyribonucleotide, while purple acid phosphatase may be involved in the regulatory mechanisms of important biological processes. For ribonucleotide reductase, Dr. Que will investigate three aspects: a) the spectroscopic properties of the diferrous form and how it interacts with dioxygen, b) the stoichiometry of tyrosyl radical formation and its implications of cluster- cluster communication via long range electron transfer, and c) the use of cryoenzymological techniques to trap intermediates in the reaction of the di-ferrous form with O2 and spectroscopic characterization of these intermediates. For purple acid phosphatase, experiments will be carried out to test a proposed active site model and a proposed mechanism of enzyme action. Physical techniques to be used include ultra- violet, visible and infra-red spectroscopy, resonance Raman spectroscopy, NMR, EPR, Mossbauer spectroscopy, magnetic circular dichroism and EXAFS.

具有由氧代或羟基桥接的双铁中心组成的活性位点的蛋白质构成了金属蛋白的新亚类。 此类包括在生物学中执行多种功能的蛋白质 - 双氧运输（血红蛋白）、氧活化（甲烷单加氧酶）、核糖核苷酸向脱氧核糖核苷酸的转化（核糖核苷酸还原酶）和磷酸酯水解（紫色酸性磷酸酶）。 该项目将重点关注后两种酶。 核糖核苷酸还原酶是脱氧核糖核苷酸生物合成的关键酶，而紫色酸性磷酸酶可能参与重要生物过程的调节机制。 对于核糖核苷酸还原酶，Que 博士将研究三个方面：a) 二铁形式的光谱特性及其如何与双氧相互作用，b) 酪氨酰自由基形成的化学计量及其通过长程电子转移对簇-簇通信的影响，以及 c) 使用低温酶学技术捕获二铁形式与双氧反应中的中间体。 O2 和这些中间体的光谱表征。 对于紫色酸性磷酸酶，将进行实验来测试拟议的活性位点模型和拟议的酶作用机制。 所使用的物理技术包括紫外、可见光和红外光谱、共振拉曼光谱、NMR、EPR、穆斯堡尔光谱、磁圆二色性和 EXAFS。