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。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。 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： 应用外消旋蛋白质结晶学来确定蛋白质分子的X射线结构，否则蛋白质分子很难结晶。 从外消旋混合物中结晶蛋白质分子(即含有等比例的L和D-蛋白质对映体的溶液)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存在反过来又可以通过直接的方法促进从头算结构的解决。我们最近通过从我们实验室生产了雪花抗冻蛋白、抗菌微蛋白plectasin、omwaprin和几种难以结晶的离子通道配体的中心对称蛋白晶体来展示这种外消旋方法。为了探索这种外消旋方法的普遍用途，我们目前正将其应用于其他化学合成的蛋白质，这些蛋白质已知仅以野生型形式顽抗结晶。我们实验室目前正在探索的蛋白质靶标包括迄今已知的最大的天然环肽棕榈醛原、胰岛素原、糖蛋白I-309和来自结核分枝杆菌Rv1738的假想蛋白质。我们还将这种方法扩展到从D-蛋白质和L-蛋白质的类似物的准外消旋混合物中获得晶体。 二、艾滋病化疗中的重要靶点HIV-1蛋白酶催化的分子细节阐明。 人们已经合成了各种化学类似物来进行催化机理的“动力学/函数”关联，并设计并集成了完全人工可调的催化装置。我们目前正在使用X射线结晶学来阐明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.