CONFORMATIONAL DYNAMICS OF ABC TRANSPORT SYSTEMS

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。三磷酸腺苷结合盒(ABC)转运蛋白在所有三个生命王国中都有表达，并在人类健康中扮演着许多重要的角色。所有的系统都可能使用一种共同的机制，将三磷酸腺苷的水解与底物的跨膜运动结合起来。我们正在研究细菌ABC(三磷酸腺苷结合盒)输入系统中的偶联机制。这些系统利用外周受体与底物结合，将其运送到膜复合体，并通过ATP结合盒激活ATP结合和水解。我们正在研究的系统是来自大肠杆菌的麦芽糖运输系统，一种易于处理的ABC转运体，以及来自金黄色葡萄球菌的异羟甲酸铁摄取系统(Fhu)，金黄色葡萄球菌是一种严重耐药感染的有机体。当受体与其配体结合时，它的构象变化似乎是激活ATPase活性的关键因素。我们的目标是通过绘制系统中的构象变化来开发运输过程的模型。我们正在通过设计外周受体来改变其构象平衡来解决这个问题，然后通过生长试验、体外转运和ATPase试验来评估功能。测量野生型和工程化受体的溶液构象对这些研究至关重要，需要从APS的光束线ID18收集数据。细菌对铁的摄取对它们的生长和毒力至关重要，这些研究可能会导致细菌感染的新疗法。

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. ATP Binding Cassette (ABC) transporters are expressed in all three kingdoms of life and play a number of important roles in human health. All systems couple ATP hydrolysis to transmembrane movement of a substrate, likely using a common mechanism. We are investigating the mechanism of coupling in bacterial ABC (ATP Binding Cassette) import systems. These systems employ a peripheral receptor that binds the substrate, delivers it to the membrane complex, and activates ATP binding and hydrolysis by the ATP binding cassettese. The systems we are investigating are the maltose transport system from E. coli, a tractable model ABC transporter, and the Ferric Hydroxamate Uptake (Fhu) system from S. aureus, an organism that is a source of serious antibiotic-resistant infections. The conformational change in the receptor when it binds its ligand appears to be a critical factor for the activation of ATPase activity. Our goal is to develop a model for the transport process by mapping the conformational changes in the system. We are approaching this problem by engineering the peripheral receptor to alter its conformational equilibrium and then assessing functionality by growth assays and in vitro transport and ATPase assays. Measuring the solution conformation of the wild-type and engineered receptors is essential for these studies and has required data collected from beamline ID18 at APS. Iron uptake by bacteria is critical for their growth and virulence, and these studies may lead to new therapies for bacterial infections.