BIOMIMETIC MODELING OF THE ACTIVE SITE OF [FE]-HYDROGENASE

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 最近由Thauer进行的生化工作允许对[Fe]-氢酶中的活性部位进行结构表征。这种氢酶是独一无二的，因为它不像[FeFe]-和[NiFe]-氢酶那样含有Fe-S簇。然而，对于双原子配体的存在，它显示了一个共同的活性中心结构基序，很可能是一氧化碳。氢酶是唯一一类含有这种对生物有毒性的配体的酶家族。我们提出了一系列多边X射线吸收测量来全面表征几种仿生化合物的电子结构和几何结构。我们的数据将允许对活性中心在组成、电子和几何结构上的几个不确定因素进行精炼。此外，XANES和EXAFS数据将使我们能够验证电子结构计算方法，这些方法将用于绘制H2形成亚甲基四氢甲烷蝶呤脱氢酶的分子机制。

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. Recent biochemical work by Thauer allowed for the structural characterization of the active site in [Fe]-hydrogenase. This hydrogenase is unique in a sense that it does not contain Fe-S clusters like the [FeFe]- and the [NiFe]-hydrogenases. However, it shows a common active site structural motif for the presence of diatomic ligands which is likely carbon monoxide. The hydrogenases are the only family of enzymes that contain this otherwise toxic ligand to living organisms. We are proposing a series of multi-edge x-ray absorption measurements to fully characterize the electronic and geometric structure of several biomimetic compounds. Our data will allow for the refinement of several uncertainties with the active site in composition, electronic, and geometric structure. Furthermore, the XANES and EXAFS data will allow us to validate electronic structure calculation methods that are to be used to map the molecular mechanism of the H2-forming methylenetetrahydromethanopterin dehydrogenase.