CRYSTALLOGRAPHY OF CHEMICALLY SYNTHESIZED PROTEINS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 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。 该项目涉及天然蛋白质（即L-蛋白质）及其镜像对映体（即D-蛋白质）的全化学合成。蛋白质分子从外消旋混合物（即含有相等比例的L-和D-蛋白质对映异构体的溶液）中结晶可导致更容易形成中心对称晶体。中心对称蛋白质晶体的可用性反过来又可以通过直接方法促进从头计算结构解。我们最近通过从我们的实验室生产Snowflee抗冻蛋白和crambin的中心对称蛋白晶体来证明这种外消旋方法。为了探索这种方法的一般效用，我们将这种方法应用于其他化学合成的蛋白质，这些蛋白质难以单独用L-蛋白质结晶，例如：抗微生物微蛋白omwaprin，有史以来已知的最大的天然环肽palicourein，一种假设的结核分枝杆菌蛋白Rv 1738。我们还将此方法推广到从D-红麻素和L-红麻素拓扑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。 合成了各种化学类似物，以执行催化机制中的“动力学/功能”相关性，并设计和整合了完全人工可调催化装置。

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. i. Application of racemic protein crystallography to determine the X-ray structure of protein molecules, which are otherwise difficult to crystallize. This project involves the total chemical synthesis of native protein (i.e. L-protein) and its mirror image enantiomer (i.e. D-protein). Crystallization of a protein molecule from a racemic mixture (i.e. a solution containing equal proportions of L- and D- protein enantiomers) can lead to more facile formation of centrosymmetric crystals. The availability of centrosymmetric protein crystals in turn can facilitate ab initio structure solution by direct methods. We have recently demonstrated this racemic approach by producing the centrosymmeric protein crystals of Snowflee antifreeze protein and crambin from our laboratory. To explore the general utility of this approach we applied this method to other chemically synthesized proteins, which were difficult to crystallize with L-protein alone such as: antimicrobial micro-protein omwaprin, the largest ever known natural cyclotide palicourein, a hypothetical mycobacterium tuberculosis protein Rv1738. We also extended this method to obtaine crystals from a quasi-racemic mixture of D-crambin and topological analogue of L-crambin. ii. Elucidation of molecular details of HIV-1 protease catalysis, an important target in AIDS chemotherapy. Various chemical analogues were synthesized to perform 'dynamics/function' correlations in catalytic mechanism as well as totally artificial tunable catalytic apparatus was designed and incorporated.