BIOCHEMICAL AND STRUCTURAL CHARACTERIZATION OF MERCURIC ION REDUCTASE

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 本项目主要研究汞离子还原酶的结构和动力学特性。汞离子还原酶由两个结构域组成，一个是催化核心区，与含有吡啶核苷酸二硫键还原酶家族的FAD高度同源，即谷胱甘肽还原酶；另一个是第二个结构域，即69个氨基酸的N-末端结构域，序列与金属结合蛋白同源。我们主要集中在两个方面：1)汞(II)结合途径中有效催化所必需的结构特征的表征；2)阐明MERA的催化核心与NmerA结构域以及核心与汞解毒途径的其他蛋白质包括MerB(有机汞裂解酶)和整合膜运输蛋白Mert或Merc之间的蛋白质/蛋白质相互作用的机制。我们使用嵌合体来图形化地显示汞(II)和其他催化核心域的络合物的结构，并与其他小分子蛋白质如NmerA或硫氧还蛋白相互作用。此外，我们使用嵌合体来帮助我们评估突变位点，并检查MERA与其他Mer途径蛋白之间对接的可能模式。

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. This project focuses on the structural and kinetic characterization of mercuric ion reductase. Mercuric ion reductase is composed of two domains, a catalytic core domain that is highly homologous to the FAD containing pyridine nucleotide disulfide reductase family i.e. glutathione reductase and a second domain, a ~69 amino acid N-terminal domain, with sequence homology to metal binding proteins. We are focusing on two aspects: 1) characterization of structural features in the Hg(II) binding pathway that are essential for efficient catalysis and 2) elucidating mechanisms of protein/protein interactions between the catalytic core of MerA and the NmerA domain as well as of core with other proteins of the mercury detoxification pathway including MerB, an organomercurial lyase, and the integral membrane transport proteins, MerT or MerC. We use Chimera to graphically present structures of Hg(II) and other complexes of the catalytic core domain alone and interacting with other small molecular weight proteins like NmerA or thioredoxin. In addition, we use Chimera to assist us in evaluating sites for mutagenesis and examining possible modes for docking between MerA and the other mer pathway proteins.