Collaborative Research: Molecular Mechanism of Heme Extraction by IsdH

为了确定一种感染，细菌病原体摄取营养物质，使其能够增殖。铁是细菌在感染期间从人类血红蛋白中主动获取的一种基本营养物质。微生物获取铁的一个关键步骤是从血红蛋白中提取富含铁的血红素。使用生物物理和计算方法，研究人员将了解病原体金黄色葡萄球菌如何使用ISDH表面受体从血红蛋白中提取血红素。这一过程在临床上很重要，因为它使耐甲氧西林金黄色葡萄球菌(MRSA)能够引起感染。这项工作的结果将提供一个详细的提取机制的视图，它将产生广泛的影响，因为其他细菌病原体也使用类似的机制在感染期间获得铁。该提案将促进博士水平上代表人数不足的学生的本科生和研究生外展计划。这笔赠款将用于支持社区大学生的外展工作，促进多样性、包容性和消除参与生物科学研究事业的障碍。在这个项目中，一个研究小组将应用计算和实验方法来破译金黄色葡萄球菌ISDH蛋白从人类血红蛋白(Hb)中提取血红素的结构、动态和能量基础。这个过程是高度保守的，许多细菌物种都使用这个过程来获得必要的营养铁。最新的结构数据和新开发的实验工具使ISDH成为探索血红素提取机制的强大模型系统。本研究项目的总体目标是阐明血红素是如何从Hb转移到ISDH的，并了解这一过程是如何通过域间运动来促进的。在目标1中，模拟和实验将定义血红素转移的途径，并发现促进转移和扭曲Hb以触发血红素释放的特定受体接触。在目标2中，结构域间运动的作用将通过定量评估它们对受体局部浓度的影响以及转移的动力学和热力学来确定。由于ISDH是典型的，该项目的结果将为广泛的细菌使用的提取机制提供广泛的洞察力。

In order to establish an infection bacterial pathogens ingest nutrients that enable them to proliferate. Iron is an essential nutrient that is actively acquired by bacteria from human hemoglobin during infections. A key step in microbial iron acquisition is the extraction of iron-laden heme from hemoglobin. Using biophysical and computational approaches the investigators will learn how the pathogen Staphylococcus aureus uses the IsdH surface receptor to extract heme from hemoglobin. This process is clinically important, as it enables methicillin resistant S. aureus (MRSA) to cause infections. The results of this work will provide a detailed view of the mechanism underlying extraction and it will have a broad impact as other bacterial pathogens also use a similar mechanism to acquire iron during infections. The proposal will facilitate undergraduate and graduate student outreach programs of students from under-represented groups at the PhD level. The grant will be used to support outreach efforts to community college students and promote diversity, inclusion, and the elimination of barriers to participation in bioscience research careers.In this project a team of investigators will apply computational and experimental methodologies to decipher the structural, dynamic and energetic basis through which the Staphylococcus aureus IsdH protein extracts heme from human hemoglobin (Hb). This process is highly conserved and used by many bacterial species to obtain the essential nutrient iron. Recent structural data and newly developed experimental tools make IsdH a powerful model system in which to explore the heme extraction mechanism. The overall goal of this research project is to elucidate how heme is transferred from Hb to IsdH, and to learn how this process is facilitated by inter-domain motions. In Aim #1, simulations and experiments will define the pathway of heme transfer, and uncover specific receptor contacts that facilitate transfer and distort Hb to trigger heme release. In Aim #2, the role of inter-domain motions will be determined by quantitatively assessing their effect on the local concentration of the receptor, and the kinetics and thermodynamics of transfer. Because IsdH is paradigmatic, the results of this project will provide broad insight into the extraction mechanisms used by a wide-range of bacteria.