STRUCTURAL INVESTIGATIONS OF METALLOPROTEIN METAL SITES

描述：（改编自申请人的摘要）的长期目标 这一建议是为了详细描述结构和功能 Zn（II）在生物系统中的性质。锌是最常见的金属 金属蛋白质，是唯一的金属，是已知的需要为每一个 酶催化的主要类别。已经分离出数百种锌蛋白质 在蛋白质中发现了数千个潜在的锌结合位点， 序列的锌水平的不平衡，或其运输的错误， 监管可能会对健康产生深远的影响。 尽管它很重要，但关于它的信息相对较少。 生物锌（II）网站，由于研究这一困难， 光谱学上的“无声”金属X射线吸收光谱法是为数不多的 能够提供非结晶材料的结构信息的方法， 将用于确定它们的结构。 提出了三个相互关联的主要目标： - X射线吸收光谱将用于表征Zn结合 一系列重要蛋白质中的位点，特别强调一种新的 一类锌烷基转移酶。 - 将对一系列的金属结合位点进行详细的比较， 结构确定的肽。第二组实验的目的是 是确定金属立体化学偏好的相对重要性， 蛋白质结构在定义金属结合位点的结构方面。为此 工作，结构将进行比较，为一系列的光谱沉默d10 金属离子（Cu（I）、（Ag（I）、Cd（II）、Hg（II））和准金属As（III）。 - X射线吸收光谱、X射线微探针成像、微探针 光谱学和X射线显微断层扫描将用于表征 锌在斑马鱼和非洲爪蟾胚胎发育中的作用空间 和时间分辨光谱将用于确定锌 胚胎发育中的物种形成。毛细管电泳/X射线联用 荧光将用于解析和表征含锌蛋白质。

DESCRIPTION: (Adapted from applicant's abstract) The long term objective of this proposal is to characterize in detail the structural and functional properties of Zn(II) in biological systems. Zinc is the most common metal found in metalloproteins and is the only metal that is known to be required for every major class of enzyme catalysis. Hundreds of zinc proteins have been isolated and thousands of potential zinc binding sites have been identified in protein sequences. Imbalances in the levels of Zn, or errors in its transport or regulation can have profound health consequence. Despite its importance, there is relatively little information available about biological Zn(II) sites due to the difficulty of studying this spectroscopically "silent" metal. X-ray absorption spectroscopy, one of the few methods able to provide structural information for non-crystalline materials, will be used to determine their structures. Three major, inter-related objectives are proposed: -X-ray absorption spectroscopy will be used to characterize the Zn binding sites in a series of important proteins, with particular emphasis on a novel class of Zn-alkyl transfer enzymes. -Detailed comparisons will be made of the metal binding sites in a series of structurally defined peptides. The objective of this second set of experiments is to determine the relative importance of metal stereochemical preference and protein structure in defining the structure of a metal binding site. For this work, structures will be compared for a series of spectroscopically silent d10 metal ions (Cu(I), (Ag(I), Cd(II), Hg(II)) and metalloids As(III). -X-ray absorption spectroscopy, x-ray microprobe imaging, microprobe spectroscopy, and x-ray microtomography will be used to characterize the role(s) of Zn in embryo development in zebra fish and Xenopus laevis. Spatially and temporally-resolved spectroscopy will be used to determine the Zn speciation in developing embryos. Coupled capillary-electrophoresis/x-ray fluorescence will be used to resolve and characterize Zn containing proteins.