Structure, Function and Dynamics of Heme Degrading Enzymes

铁是大多数生物体的必需营养素，包括病原菌。病原菌 试图殖民人类面临着极低浓度的游离铁。因此，委员会认为， 许多病原体已经进化出了复杂的铁获取机制，包括利用 血红素铁此外，最近的研究表明，在感染的早期阶段，葡萄球菌 金黄色葡萄球菌喜欢铁而不喜欢血红素。因此，有可能致病菌使用的靶向途径， 从其宿主中同化铁和血红素铁是开发新抗生素的可行途径。 在条件致病菌中，许多参与血红素摄取和血红素利用的蛋白质 铜绿假单胞菌具有指定的功能。然而，结构，动力学和蛋白质间 促进宿主血红素捕获、内化和在胞质溶胶中降解的相互作用主要是 未知在本申请中，我们提出通过研究其结构、功能， 动力学和可溶性蛋白质的协会，帮助从血红蛋白中捕获血红素，并帮助 在铜绿假单胞菌的胞液中降解。本研究的重要成果有：（1）生物化学 和两个以前未知的电子传递蛋白（Bfd和Fpr）的结构特征，我们 假设功能提供血红素加氧酶所需的7个电子，以切割血红素并释放 铜绿假单胞菌胞液中的铁。我们还计划研究蛋白质-蛋白质相互作用， 促进电子从Bfd转移到血红素加氧酶，以支持血红素的降解。(2)结构 HasAp是一种分泌型血红素结合蛋白，能够从血红蛋白中捕获血红素， 将其传递到外膜受体进行内化。所获得的HasAp的结构信息 将用于定义其与血红蛋白的相互作用（3）多肽动力学如何表征 有助于铜绿假单胞菌血红素加氧酶的血红素氧化活性，在这一点上， 这在很大程度上是由于在即将到期的供资周期中所支持的工作。从这些信息中了解到的信息 研究有望为未来设计新的治疗策略提供几个切入点 旨在干扰铜绿假单胞菌中血红素的吸收和降解。

Iron is an essential nutrient for most organisms, including pathogenic bacteria. Pathogenic bacteria attempting to colonize humans are confronted with extremely low concentrations of free iron. Consequently, many pathogens have evolved sophisticated mechanisms for iron acquisition, including the utilization of heme-iron. Moreover, it has been recently shown that during the early stages of infection Staphylococcus aureus prefers iron from heme. Thus, it is possible that targeting paths used by pathogenic bacteria to assimilate iron and heme-iron from their host is a viable approach to de development of new antibiotics. Many of the proteins involved in heme uptake and heme utilization in the opportunistic pathogen Pseudomonas aeruginosa have designated functions. However, the structure, dynamics and inter-protein interactions that facilitate host-heme capture, internalization and degradation in the cytosol are largely unknown. In this application we propose to contribute to fill this gap by studying the structure, function, dynamics and association of the soluble proteins that aid in the capture of heme from hemoglobin and help degrade it in the cytosol of P. aeruginosa. Important outcomes of the proposed studies are:(1) Biochemical and structural characterization of two previously unknown electron transport proteins (Bfd and Fpr), which we hypothesize function to deliver the 7 electrons needed by heme oxygenase to cleave the heme and release its iron in the cytosol of P. aeruginosa. We also plan to investigate the protein-protein interactions that facilitate electron transfer from Bfd to heme oxygenase to support the degradation of heme. (2) Structural characterization of HasAp, a secreted heme binding protein capable of capturing heme from hemoglobin and delivering it to the outer membrane receptor for internalization. The acquired structural information of HasAp will be used to define its interactions with hemoglobin (3) Characterization of how polypeptide dynamics contribute to the heme oxidation activity of heme oxygenasefrom P. aeruginosa, which at this point is better understood largely due to work supported in the expiring funding cycle. The information learned from these investigations is expected to provide several entry points for the future design of novel therapeutic strategies aimed at interfering with heme uptake and degradation in P. aeruginosa.