BIOCHEMICAL AND STRUCTURAL CHARACTERIZATION OF MERCURIC ION REDUCTASE

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 该项目的重点是汞离子还原酶的结构和动力学表征。 汞离子还原酶由两个结构域组成，一个是与含有吡啶核苷酸二硫键还原酶家族（即谷胱甘肽还原酶）的FAD高度同源的催化核心结构域，另一个是与金属结合蛋白具有序列同源性的约69个氨基酸的N-末端结构域。 我们的重点是两个方面：1）在汞（II）结合途径的结构特征的表征，是必要的有效催化和2）阐明蛋白质/蛋白质之间的相互作用的机制的催化核心的MerA和NmerA结构域，以及核心与其他蛋白质的汞解毒途径，包括MerB，有机汞裂解酶，和完整的膜转运蛋白，MerT或MerC。 我们使用嵌合体以图形方式呈现Hg（II）和催化核心结构域的其他复合物的结构，并与其他小分子量蛋白质如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诱变位点，并检查MerA和其他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. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. 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.