EFFECT OF PROTEIN MUTATION ON ACTIVE SITE STRUCTURE IN CYTOCHROME C

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。 Fe K边XAS数据将在电子转移蛋白细胞色素c（cytc）上测量。具有组氨酸-蛋氨酸（His-Met）铁配位的C型细胞色素在电子转移反应和酶中起重要作用。轴向甲硫氨酸配体在稳定蛋白质和维持低氧化还原电位方面起主要作用。铜绿假单胞菌（Pa）和欧洲亚硝化单胞菌（Ne）cytc的蛋白质突变在其活性位点中显示菱形性（使用EPR光谱）的差异，这与Fe-S（Met）键中的扰动有关。 Fe K边EXAFS数据（BL 9 -3）将揭示特定的几何结构的变化，在电子转移活性位点的蛋白质环境的变化。实验将扩展到S K边XAS（BL 4 -3），以获得Fe-S共价性的定量信息。

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. Fe K-edge XAS data will be measured on the electron transfer protein cytochrome c (cytc). The c-type cytochromes that have histidine-methionine (His-Met) iron coordination play important roles in electron-transfer reactions and in enzymes. The axial methionine ligand plays a major role in stabilizing the protein and maintaining a low redox potential. Protein mutations of Pseudomonas aeruginosa (Pa) and Nitrosomonas europeae (Ne) cytc show differences in rhombicity (using EPR spectroscopy) in their active site, which have been linked to perturbations in the Fe-S(Met) bond. Fe K-edge EXAFS data (BL9-3) will shed light on specific geometric structure changes at the electron-transfer active site with changes in the protein environment. The experiments will be extended to S K-edge XAS (BL4-3) to obtain quantitative information on the Fe-S covalency.