DYNAMICS & INTERPROTEIN INTERACTIONS IN RELEASE OF IRON IN BACTERIOFERRITIN

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 引起诸如呼吸道感染（流感嗜血杆菌）、肠道病症（志贺氏菌）和机会性铜绿假单胞菌等疾病的生物体已经开发出从其宿主中螯合铁的复杂机制。入侵的病原体和它们的宿主之间对营养素的激烈竞争导致了新的抗菌剂可能针对铁的获得和体内平衡的想法。为了更深入地研究这一观点，重要的是要从分子水平上了解病原体管理铁的机制，从获取和内化到储存和利用。重大进展提高了我们对铜绿假单胞菌和许多其他病原体铁摄取的理解。相比之下，人们对内化铁的命运知之甚少。 控制铁毒性的一种机制是将铁储存在铁蛋白和细菌铁蛋白中，这是一种能够在其内部空腔中储存多达4，000个铁原子的大蛋白质。尽管铁蛋白和细菌铁蛋白在调节铁浓度和防止其毒性作用方面的重要性，但对提供Fe 2+用于储存的过程或促使其释放以安全整合代谢的信号知之甚少。我们最近证明，铁离子从铜绿假单胞菌的细菌铁蛋白A（BfrA）的动员需要从铁氧还蛋白还原酶（FPR）的电子转移。因此，BfrA-FPR复合物是研究细菌铁蛋白如何识别其生理调节剂以及结合是否调节细菌铁蛋白的动态特性以促进铁释放的前所未有的机会。 为了填补这些空白，我们计划：（1）研究BfrA的动态特性，利用专门为研究大蛋白质而定制的策略，使用氢/氘H/D交换耦合到NMR光谱。(2)利用计算方法研究BfrA的动力学性质;（3）利用计算和HD/NMR方法研究BfrA与FPR的结合方式，并确定蛋白质间结合对BfrA动力学性质的影响。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Organisms causative of diseases such as respiratory tract infections (Haemophilus influenzae), enteric conditions (Shigella dysenteriae) and the opportunistic Pseudomonas aeruginosa have developed sophisticated mechanisms for sequestering iron from their host. This intense competition between invading pathogens and their host for the nutrient has led to the idea that new antimicrobials may target iron acquisition and homeostasis. To study this idea more closely, it is important to gain molecular-level understanding of the mechanisms by which pathogens manage iron, from acquisition and internalization to storage and utilization. Significant advances have improved our understanding of iron uptake by P. aeruginosa and many other pathogens. In comparison, little is known about the fate of internalized iron. One mechanism whereby iron toxicity is controlled is by storage of iron in ferritin and bacterioferritin, which are large proteins capable of storing up to 4,000 iron atoms in their internal cavities. Despite the importance of ferritins and bacterioferritins in regulating iron concentrations and preventing its toxic effects, little is known about the processes that deliver Fe2+ for storage or the signals that prompt its release for safe integration in metabolism. We have recently demonstrated that mobilization of Fe2+ from bacterioferritin A (BfrA) in P. aeruginosa requires electron transfer from a ferredoxin reductase (FPR). Thus the BfrA-FPR complex is an unprecedented opportunity to investigate how bacterioferritins recognize their physiological regulators and if binding modulates the dynamic properties of the bacterioferritin to facilitate iron release. To fill these gaps we plan to: (1) Investigate the dynamic properties of BfrA utilizing a strategy specifically tailored to study large proteins using hydrogen/deuterium H/D exchange coupled to NMR spectroscopy. (2) Investigate the dynamic properties of BfrA with the aid of computational methods and (3) Utilize computational and HD/NMR methods to investigate how BfrA binds to FPR and determine the effect that the inter-protein association exerts on the dynamic properties of BfrA.