XAS STUDIES ON HEME PROTEINS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 利用X射线吸收光谱对血红素蛋白进行了广泛的研究，但新的蛋白质/作用仍在不断涌现。XANES和多重散射XAFS研究是研究它们的氧化态、配位数和配位配体性质的灵敏探针。我们将从脑红蛋白(NB)在脑中的作用、肌红蛋白(Mb)在心血管疾病中的NO结合和其他功能以及肾脏中的新蛋白质吲哚胺2，3-双加氧酶-2(IDO-2)方面研究血红素的结构。我们将使用这些技术来比较分离蛋白质的不同加合物和氧化状态的结构与细胞内包含的那些结构。特别是，NB是否在脑缺血时提供神经保护是有争议的，我们计划研究正常情况下以及与中风和神经退行性疾病相关的神经元细胞内脑红蛋白结构的变化。同样，不与Mb结合对心血管系统的健康很重要，但尚不确定它是否与体内人类Mb中的硫基、血红素中心或两者结合。我们将把分离蛋白质的XAS数据与细胞中在正常条件下以及与心血管疾病相关的各种条件下发现的数据进行比较。最后，最近发现的IDO-2代谢色氨酸，就像研究得很好的IDO(现在被称为IDO-1)一样。然而，与IDO-1不同的是，IDO-2在分离和纯化蛋白质时失去了活性。XAS将用于研究分离过程中发生的结构变化，以确定体内可能的活性结构。这一点很重要，因为越来越多的证据表明，肾脏中的IDO-2在控制血压方面具有作用，因此，了解这种活性形式的性质以及如何调节其活性来控制血压，在治疗低血压和高血压方面具有许多潜在的应用。

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. Heme proteins have been studied extensively by x-ray absorption spectroscopy, but new proteins/roles continue to emerge. XANES and multiple-scattering XAFS studies are sensitive probes of their oxidation state, coordination number and the nature of the coordinating ligands. We will study the heme structures with respect to the roles of neuroglobin (Nb) in the brain, NO binding and other functions of myoglobin (Mb) in cardiovascular disease, and the new protein, indoleamine 2,3-dioxygenase-2 (IDO-2), in the kidneys. We will use these techniques to compare the structures of different adducts and oxidation states of the isolated proteins with those contained within cells. In particular, whether Nb confers neuro-protection during cerebral ischemia is controversial and we plan to study changes in the structures of intracellular neuroglobin in neurons under normal conditions and those associated with stroke and neurodegenerative diseases. Similarly, NO binding to Mb is important in the health of the cardiovascular system, but it is uncertain as to whether it binds to the thiolate group, the heme centre or both in human Mb in vivo. We will compare the XAS data from isolated proteins with those found in cells under various conditions associated with normal conditions and those associated with cardiovascular disease. Finally, the recently discovered IDO-2 metabolizes tryptophan, like the well-studied IDO (now known as IDO-1). However, IDO-2, unlike IDO-1, loses its activity when the protein is isolated and purified. XAS will be used to study the structural changes that occur during the isolation procedures in order to ascertain the likely active structure in vivo. This is important as there is mounting evidence that IDO-2 in the kidney has a role in controlling blood pressure and, hence, understanding the nature of the active form and how its activity may be modulated to control blood pressure has many potential applications in the treatment of both low and high blood pressure.