STRUCTURE OF MODULAR EXTRACELLULAR ADHERENCE PROTEIN FROM S AUREUS & COMPLEXES

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来源获得了主要资金，因此可以在其他CRISP条目中表示。所列机构为中心机构，不一定为研究者机构。金黄色葡萄球菌是一种广泛存在的持久性病原体，可引起人类和动物的广泛感染。S的起始。金黄色葡萄球菌感染需要多种多样的毒力决定因子，包括外切酶、毒素和许多蛋白质粘附素。S.金黄色葡萄球菌通过介导大量宿主配体（例如纤维蛋白原、纤连蛋白和玻连蛋白）与细菌细胞之间的相互作用而作为分泌的毒力因子起作用，并且最近的遗传和生物化学研究表明Eap介导的蛋白质-蛋白质相互作用在金黄色葡萄球菌中起核心作用。金黄色葡萄球菌致病性。作为理解这些医学上重要的相互作用的第一步，我们最近确定了全长Eap蛋白中存在四个拷贝的重复结构域（EAP结构域）的三种晶体结构。本项目的目标是通过确定：（a）全长Eap蛋白的结构和（B）Eap-配体相互作用的生化和结构机制来扩展EAP结构域结构的这些先前研究。Eap的模块化性质及其大小（50 kDa）已经排除了通过NMR和X射线晶体学的传统方法对全长蛋白质进行彻底的结构表征。相比之下，小角X射线散射（SAXS）已被证明是一个非常有价值的工具，在确定精确的这种类型的分子的结构特性。SAXS的能力还将使我们能够实现几种医学上重要的Eap复合物的第一次结构表征，包括具有a）人纤维蛋白原（Fg）、B）人细胞间粘附分子-1（ICAM-1）、c）人纤连蛋白（Fn）和d）S.金黄色葡萄球菌细胞表面相关中性磷酸酶（NAPs）。这些研究将进一步加深我们对感染过程所必需的几个分子事件的理解，并可能提出治疗这些感染的新方法。

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. Staphylococcus aureus is a widespread, persistent pathogen that causes a broad range of infections in humans and animals. Initiation of S. aureus infections requires a diverse array of virulence-determining factors, including exoenzymes, toxins, and numerous protein adhesins. The Extracellular Adherence Protein (Eap) of S. aureus functions as a secreted virulence factor by mediating interactions between abundant host ligands (e.g. fibrinogen, fibronectin, and vitronectin) and the bacterial cell, and recent genetic and biochemical studies have shown that Eap-mediated protein-protein interactions serve a central role in S. aureus pathogenesis. As a first step toward understanding these medically-important interactions, we recently determined three crystal structures of the repeating domain (EAP domain) present in four copies in the full-length Eap protein. The goal of this project is to expand upon these previous studies of EAP domain structure by determining: (a) the structure of the full-length Eap protein and (b) the biochemical and structural mechanisms that underlie Eap-ligand interactions. The modular nature of Eap and its size (50 kDa) have precluded a thorough structural characterization of the full-length protein by the traditional approaches of NMR and x-ray crystallography. In contrast, small angle X-ray scattering (SAXS) has proven to be an exceedingly valuable tool in determining the structural properties of precisely this type of molecule. The capabilities of SAXS will also allow us to achieve the first structural characterization of several medically-important Eap complexes, including those with a) human Fibrinogen (Fg), b) human Intercellular Adhesion Molecule-1 (ICAM-1), c) human Fibronectin (Fn), and d) the S. aureus cell surface-associated neutral phosphatase (NPase). These studies will further our understanding of several molecular events essential to the infection process and may suggest novel approaches to treating these infections.