CRYSTALLOGRAPHY OF CHEMICALLY SYNTHESIZED PROTEINS

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。子项目的主要支持 子项目的主要研究者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 表示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。 蛋白质的化学合成使我们能够以独特的方式了解蛋白质功能的化学基础。 正在进行的项目如下： I.外消旋蛋白质晶体学的应用，以确定蛋白质分子的X射线结构，否则难以结晶。 从外消旋混合物（即含有相等比例的L-和D-蛋白对映异构体的溶液）中结晶蛋白质分子可以极大地促进高度有序的中心对称晶体的形成。中心对称蛋白质晶体的可用性反过来可以促进从头计算结构的直接方法解决方案。我们最近已经证明了这种外消旋的方法，通过生产中心对称的蛋白质晶体的雪抗冻蛋白，抗菌微蛋白plectasin，omwaprin和几个难以结晶的离子通道配体从我们的实验室。为了探索这种外消旋方法的一般效用，我们目前正在将其应用于其他化学合成的蛋白质，已知这些蛋白质单独以其野生型形式结晶。我们实验室目前正在探索的蛋白质靶点包括已知最大的天然环肽palicourein，胰岛素原，糖蛋白I-309和结核分枝杆菌Rv 1738的假设蛋白质。我们还将这种方法扩展到从D-蛋白和L-蛋白类似物的准外消旋混合物中获得晶体。 二.阐明HIV-1蛋白酶催化的分子细节，这是艾滋病化疗的重要靶点。 已经合成了各种化学类似物以在催化机理中执行“动力学/功能”关联，并且已经设计并并入了完全人工可调谐催化装置。我们目前正在使用X射线晶体学来阐明HIV-1蛋白酶催化的分子细节。

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. The chemical synthesis of proteins allows us to understand the chemical basis of protein function in unique ways. Ongoing projects are the following: i. Application of racemic protein crystallography to determine the X-ray structure of protein molecules, which are otherwise difficult to crystallize. Crystallization of a protein molecule from a racemic mixture {i.e. a solution containing equal proportions of L- and D- protein enantiomers} can greatly facilitate the formation of highly ordered centrosymmetric crystals. The availability of centrosymmetric protein crystals can in turn facilitate ab initio structure solution by direct methods. We have recently demonstrated this racemic approach by producing centrosymmeric protein crystals of Snowflee antifreeze protein, antimicrobial microprotein plectasin, omwaprin and several difficult to crystallize ion channel ligands from our laboratory. To explore the general utility of this racemic method we are currently applying this to other chemically synthesized proteins, which are known to be recalcitrant to crystallization in their wild type form alone. The list of protein targets currently being explored in our laboratory includes the largest ever known natural cyclotide palicourein, proinsulin, glycoprotein I-309 and a hypothetical protein from mycobacterium tuberculosis Rv1738. We are also extending this method to obtain crystals from a quasi-racemic mixture of D-protein and an analogue of L-protein. ii. Elucidation of molecular details of HIV-1 protease catalysis, an important target in AIDS chemotherapy. Various chemical analogues have been synthesized to perform 'dynamics/function' correlations in catalytic mechanism as well as totally artificial tunable catalytic apparatus have been designed and incorporated. We are currently using X-ray crystallography to elucidate the molecular details of HIV-1 protease catalysis.