IRON TRANSPORT, SYNERGISTIC ANIONS

铁传输，协同阴离子

• 批准号: 7369162
• 负责人: BRIAN H SHILTON
• 金额: $ 0.29万
• 依托单位: ILLINOIS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7369162
• 关键词: IRON; TRANSPORT; SYNERGISTIC; ANIONS

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. We are investigating the mechanism of an iron uptake system that is important for survival of pathogenic Staphylococcus aureus in iron-limited media. The Ferric Hydroxamate Uptake ("Fhu") system is able to recognize and assimilate ferric hydroxamate siderophores; it is comprised of an integral membrane ABC transporter complex and peripheral binding proteins, FhuD1 and FhuD2. We are particularly interested in the ferric siderophore binding proteins because they have a high affinity for a structurally diverse collection of siderophores and could be used to deliver antibiotics to the bacteria in a "Trojan Horse" manner. Using SAXS at beamiline ID18, we demonstrated that FhuD1 and FhuD2 undergo only a very small conformational change when they bind ligand. In fact, recent measurements indicate that the extent of the conformational change depends on the exact nature of the siderophore. The role of the siderophore and the binding protein in the transport mechanism are discussed in our publications. Importantly, the structural information provided by SAXS data has led us to conclude that recognition of the ligand by the ABC transport complex is a critical part of the transport mechanism for the Fhu system. We are also using conformational engineering of maltose binding protein (MBP) in E. Coli to assess the relative roles of the binding protein and ligand in triggering ATP hydrolysis by the integral membrane complex. SAXS data obtained at beamline ID18 have been absolutely critical for rapid and accurate evaluation of the effect of our mutations on the conformation of MBP.

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来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。我们正在研究铁摄取系统的机制，这是重要的致病性金黄色葡萄球菌在铁有限的介质中的生存。羟肟酸铁摄取（“Fhu”）系统能够识别和同化羟肟酸铁铁载体;它由整合的膜ABC转运蛋白复合物和外周结合蛋白FhuD 1和FhuD 2组成。我们特别感兴趣的铁载体结合蛋白，因为他们有一个高亲和力的铁载体的结构多样的集合，并可用于提供抗生素的细菌在“特洛伊木马”的方式。使用SAXS在beamiline ID 18，我们证明，FhuD 1和FhuD 2只经历一个非常小的构象变化时，他们结合配体。事实上，最近的测量表明，构象变化的程度取决于铁载体的确切性质。铁载体和结合蛋白在运输机制中的作用在我们的出版物中进行了讨论。重要的是，由SAXS数据提供的结构信息使我们得出结论，ABC转运复合物对配体的识别是Fhu系统转运机制的关键部分。我们还利用构象工程改造麦芽糖结合蛋白（MBP）在大肠杆菌中。大肠杆菌中，以评估结合蛋白和配体在触发ATP水解的完整膜复合物的相对作用。在光束线ID 18处获得的SAXS数据对于快速准确地评估我们的突变对MBP构象的影响是绝对关键的。