Metal Cluster Active Sites in Proteins

蛋白质中的金属簇活性位点

• 批准号: 9405723
• 负责人: Lawrence Que
• 金额: $ 43.04万
• 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: 1994
• 资助国家: 美国
• 起止时间: 1994-09-01 至 1999-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9405723&HistoricalAwards=false
• 关键词: Metal; Cluster; Active; Sites; Proteins

9405723 Que Proteins with active sites consisting of diiron centers connected by a single oxygen atom bridge and/or carboxylates comprise a new subclass of metalloproteins. This growing class includes dioxygen activating enzymes such as methane monooxygenase, ribonucleotide reductase, and stearoyl ACP delta9 desaturase, and hydrolytic enzymes such as the purple acid phosphatases. A major goal of this proposal is to determine how the diiron sites of the different proteins are interrelated by comparing their spectroscopic properties in the various oxidation states. A second goal, which is specific for the dioxygen activating enzymes, is to understand the mechanisms of oxygen activation by characterizing transient species observed in the reaction of dioxygen with the diiron(II) states of these enzymes. A third goal, which is specific for the purple acid phosphatases, is to determine the roles the two metal centers play in the hydrolytic mechanism. %%% This project is aimed at understanding how a new class of metalloenzymes with active sites consisting of two iron centers catalyzes metabolically important reactions. For example, methane monooxygenase converts methane to methanol under mild conditions, in contrast to the current energy-intensive industrial process. On the other hand, ribonucleotide reductase is responsible for making deoxyribonucleotides, the building blocks of DNA, during cell growth. Using a variety of spectroscopic methods as probes, we will compare the active sites of these enzymes in their various forms to understand their structural relationship, how they catalyze their respective reactions, and the roles of the individual metal centers in carrying out the reactions. ***

具有活性位点由单氧原子桥连接的双铁中心和/或羧酸盐组成的蛋白构成了一个新的金属蛋白亚类。这类生长的酶包括双氧激活酶，如甲烷单加氧酶、核糖核苷酸还原酶和硬脂酰ACP去饱和酶，以及水解酶，如紫色酸性磷酸酶。本提案的主要目标是通过比较不同蛋白质在不同氧化态下的光谱特性来确定它们的双铁位点是如何相互关联的。第二个目标，这是特定于双氧激活酶的，是通过表征在这些酶的双氧与双铁（II）状态反应中观察到的瞬态物种来理解氧激活的机制。第三个目标是确定两个金属中心在水解机制中所起的作用，这是紫色酸性磷酸酶所特有的。该项目旨在了解一类具有两个铁中心活性位点的新型金属酶是如何催化代谢重要反应的。例如，甲烷单加氧酶在温和的条件下将甲烷转化为甲醇，这与目前的能源密集型工业过程形成鲜明对比。另一方面，核糖核苷酸还原酶在细胞生长过程中负责制造脱氧核糖核苷酸，脱氧核糖核苷酸是DNA的组成部分。利用多种光谱方法作为探针，我们将比较这些酶在不同形式下的活性位点，以了解它们的结构关系，它们如何催化各自的反应，以及单个金属中心在进行反应中的作用。＊＊＊