Structure, Function and Dynamics of Heme Degrading Enzymes

铁是包括病原细菌在内的大多数生物体的基本营养物质。病原菌 试图殖民人类的人面临着游离铁浓度极低的问题。因此， 许多病原体已经进化出获得铁的复杂机制，包括利用 亚铁血红素。此外，最近的研究表明，在感染的早期阶段，葡萄球菌 金星更喜欢从亚铁血红素中提取铁。因此，病原菌使用的靶向路径有可能 从宿主吸收铁和血红素铁是开发新抗生素的可行方法。 许多参与机会致病菌对血红素的吸收和利用的蛋白质 铜绿假单胞菌具有特定的功能。然而，蛋白质的结构、动力学和相互作用 促进宿主-血红素捕获、内化和胞浆降解的相互作用在很大程度上是 未知。在这一应用中，我们建议通过研究结构、功能、 有助于从血红蛋白中捕获血红素的可溶性蛋白的动态和相互作用 在铜绿假单胞菌的胞浆中降解。拟议研究的重要成果是：(1)生化 和两个以前未知的电子传递蛋白(BFD和FPR)的结构特征，我们 假说功能传递血红素加氧酶切割和释放血红素所需的7个电子 铜绿假单胞菌胞质中的铁。我们还计划研究蛋白质-蛋白质之间的相互作用 促进从BFD到血红素加氧酶的电子转移，以支持血红素的降解。(2)结构 HasAp是一种能从血红蛋白中捕获血红素的分泌型血红素结合蛋白 将其输送到外膜受体进行内化。获得的HasAp的结构信息 将被用来定义它与血红蛋白的相互作用(3)多肽动力学的表征 对铜绿假单胞菌的血红素加氧酶的血红素氧化活性的贡献，在这一点上是更好的 这在很大程度上是由于即将到期的供资周期所支持的工作。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。 目的是干扰铜绿假单胞菌对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.