ULTRA-HIGH RESOLUTION STRUCTURE OF NATIVE AND ENZYME INTERMEDIATE OF CYTOCHROME

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。所列机构为中心机构，不一定为研究者机构。来自酵母的细胞色素c过氧化物酶（CcP）是一种可溶性含血红素的蛋白质，存在于线粒体电子传递链中，它可能保护细胞免受有毒过氧化物的侵害。它催化两分子亚铁细胞色素c氧化为亚铁细胞色素c，同时过氧化氢还原为水。在与过氧化氢的反应循环过程中，它形成称为化合物I的半稳定中间体，其半衰期为约6小时。化合物I含有以Trp 191为中心的半稳定自由基和氧铁基（Fe 4 +=O）血红素基团。本研究的目的是获得一个可靠的结构的天然CcP和它的酶中间体化合物I的近原子分辨率，以便研究与底物的反应的结构细节，并确定的Trp 191自由基的性质，不能通过常规方法确定。

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. Cytochrome c peroxidase (CcP) from yeast is a soluble heme-containing protein found in the mitochondrial electron transport chain where it probably protects against toxic peroxides. It catalyzes the oxidation of two molecules of ferrocytochrome c to ferricytochrome c concomitant with the reduction of hydrogen peroxide to water. During the course of the reaction cycle with hydrogen peroxide it forms a semi-stable intermediate termed Compound I, which has a half-life of about 6 h. The Compound I contains a semi-stable radical centered on Trp191 and an oxyferryl (Fe4+=O) heme group. The aim of this study is to obtain a reliable structure of the native CcP and its enzyme intermediate Compound I to near atomic resolution so as to study the structural details of the reaction with substrates and to determine the nature of Trp191 radical which cannot be determined by conventional methods.