Resonance Raman Studies of Mammalian Heme Proteins

该计划的长期研究目标是在分子水平上了解血红素蛋白的显著功能多样性，血红素蛋白是生物系统中至关重要的物质，一般来说，特别是在人类生理学中。血红素位点参与和促进许多关键的生化过程，包括氧和电子传递，以及消除内部产生和环境积累的毒素，其固有的反应性受到与相关多肽的分子间相互作用的有效调节，并进一步受到与其他蛋白质和小调节分子的分子间相互作用的控制。除了更稳定的初始状态和最终状态外，人们对稍纵即逝但功能重要的瞬态或中间状态也很感兴趣。本研究计划的基本策略是应用强大的光谱探针，特别是共振拉曼和时间分辨共振拉曼技术，以天然和有策略地操纵蛋白质，以揭示这种血红素基团反应性调节的分子基础。事实上，通常情况下，这些特殊的方法是对这些地点的唯一有效的探测。在本提案中要解决的具体系统是哺乳动物生理学中涉及的血红素蛋白的三个重要类别；细胞色素P450，它催化异种生物的转化，为它们的消除做准备；鸟苷酸环化酶是神经递质NO最重要的受体分子，在人体生理中起着至关重要的调节作用；最后，一组

The long term research goals of this program are to attain a molecular level understanding of the remarkable functional diversity of heme proteins, substances that are of critical importance in biological systems, in general, and in human physiology in particular. In participating in and facilitating many critical biochemical processes, including oxygen and electron transport, as well as the elimination of internally generated and environmentally accumulated toxins, the inherent reactivity of the heme sites are effectively regulated by intermolecular interactions with the associated polypeptides and further controlled by intermolecular interactions with other proteins and small regulatory molecules. In addition to the more stable initial and final states, a great deal of interest is attached to the fleeting, but functionally important, transient or intermediate states.The essential strategy of this research program is to apply powerful spectroscopic probes, especially resonance Raman and time-resolved resonance Raman techniques, to the native and strategically manipulated proteins in order to reveal the molecular basis for this modulation of heme group reactivity. In fact, it is often the case that these particular methods are uniquely effective probes of these sites. The specific systems to be addressed in the present proposal are three important classes of heme proteins involved in mammalian physiology; cytochromes P450, which catalayze the conversion of xenobiotics, preparing them for elimination; guanylate cyclase, the most important receptor molecule for the neurotransmitter, NO, which serves a crucial regulatory function in human physiology; and, finally, a group of enzymes known as peroxidases that play a critical role in human defence against invading microorganisms.