ATOMIC RESOLUTION STUDIES OF KETOSTEROID ISOMERASE CATALYSIS

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来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。酮甾体异构酶（KSI）联盟项目是六个实验室（Boxer、Dawson、Herschlag、克恩、Petsko和通格）之间的合作努力，旨在应用多种互补方法以前所未有的细节表征和理解酶催化。该项目的晶体学部分将专注于获得KSI与底物、中间体类似物和产物结合的原子分辨率结构，以及含有非天然氨基酸的化学合成KSI的结构。这些结构研究的最终目标是（1）调查，在原子分辨率，野生型和突变酶的活性位点的结构变化，在几个关键步骤沿着反应坐标和（2）表征原子的波动和构象异质性的活性位点使用各向异性位移参数细化和时间平均分子动力学细化。这些信息将与热力学、动力学、光谱学和计算结果相结合，以严格表征催化剂催化能力的物理基础。

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. The ketsosteroid isomerase (KSI) consortium project is a collaborative effort among six laboratories (Boxer, Dawson, Herschlag, Kern, Petsko, and Tonge) to apply multiple complementary approaches toward characterizing and understanding enzymatic catalysis in unprecedented detail. The crystallographic portion of this project will focus on obtaining atomic resolution structures on the KSI bound to substrate, an intermediate analog, and product, as well as the structures of chemically synthesized KSI containing non-natural amino acids. The ultimate goals of these structural studies are (1) to investigate, at atomic resolution, structural changes in the active sites of the wild-type and mutant enzymes at several key steps along the reaction coordinate and (2) to characterize atomic fluctuations and conformational heterogeneity in the active site using both anisotropic displacement parameter refinement and time averaged molecular dynamics refinement. This information will be used in combination with thermodynamic, kinetic, spectroscopic and computational results to rigorously characterize the physical basis of the catalytic power of th