METAL CHELATION IN PROTEINS WITH POLYMETALLIC CLUSTERS

重点是形成金属硫醇盐的富含半胱氨酸的蛋白质 多金属簇 这类的范例是金属硫蛋白（MT）。 Zn（II）诱导的多金属团簇具有独特的性质， Cu（I）离子。 一个目标是确定结构性 根据形成的集群类型，MT中的重组。 第二 目的是确定类似的集群结构是否会改变 这些蛋白质三级折叠和功能。 三类分子 将被研究。 首先，一种新的金属硫蛋白， 阿尔茨海默病将被调查。 MT，指定为GIF， 生长抑制因子，在抑制树突形成中是有效的。 阿尔茨海默氏症脑提取物诱导的神经元。 纠结的枝蔓 阿尔茨海默病的神经元特征可能与 阿尔茨海默氏症脑组织中GIF的低浓度。 我们提出 实验以确定GIF的哪种金属构象体在 逆转阿尔茨海默氏症提取物诱导的神经元增殖。 一 一系列的实验提出了映射的GIF负责的部分 for activity活动. 我们计划在GIF中描述金属簇的特征， 确定MT和GIF中的序列差异是否影响性质 多金属团簇。 第二类蛋白质包括两种 真菌转录因子 ACE和AMT 1。 Cu（I）与ACE结合！和 AMT 1激活MT基因转录激活因子， 酿酒酵母和光滑念珠菌。 我们提出 为了表征这两种化合物中的Cu（I）硫醇多金属簇合物， 蛋白质构象 CuACE 1和CuAMT 1的DNA结合位点将是 其特征在于，目的是阐明 转录活性CuAMT 1/DNA复合物。 第三类是 富含半胱氨酸的序列基序，命名为LIM。 金属中心分为两部分 LIM结构域蛋白，称为富半胱氨酸蛋白（CRP）和半胱氨酸- 将研究丰富的肠蛋白（CRIP），以确定LIM是否 蛋白质表现出金属诱导的构象动力学。 中央 假设这类蛋白质的结构和功能 受到金属中心的配位化学的影响。 我们 最终想要确定特定金属离子结合在 功能 这三类分子表现出广泛的 调节DNA转录的生理功能（ACE 1和 AMT 1），金属离子缓冲（MT），神经元生长抑制（GIF）， 蛋白质-蛋白质相互作用（CRP）和可能的金属转运（CRIP）。

The focus is on cysteine-rich proteins that form metal thiolate polymetallic clusters. A paradigm of this class is metallothionein (MT). Polymetallic clusters with distinct properties are induced by Zn (II) and Cu(I) ions. One goal is to determine the magnitude of structural reorganization in MT depending on the type of cluster formed. A second objective is to determine whether similar cluster structure alter the tertiary fold and function of these proteins. Three classes of molecules will be studied. First, a novel metallothionein implicated in Alzheimer's disease will be investigated. The MT, designated as GIF for Growth Inhibitory Factor, is active in inhibiting dendrite formation in neurons induced by Alzheimer's brain extracts. The tangled outgrowths of neurons that is characteristic of Alzheimer's disease may relate to the low concentration of GIF in Alzheimer's brain tissue. We propose experiments to determine which metallo-conformer of GIF is active in reversing the Alzheimer's extract induced proliferation of neurons. A series of experiments are proposed to map the segment of GIF responsible for activity. We plan to characterize the metal clusters in GIF to determine whether sequence differences in MT and GIF affect properties of the polymetallic clusters. The second class of proteins includes two fungal transcription factors. ACE and AMT1. Cu(I) binding to ACE! and AMT1 activates the factors for transcriptional activation of MT genes in Saccharomyces cerevisiae and Candida glabrata, respectively. We propose to characterize the Cu(I) thiolate polymetallic clusters in these two protein conformations. DNA binding sites of CuACE1 and CuAMT1 will be characterized with the goal of elucidating the structure of the transcriptionally active CuAMT1/DNA complex. The third class is the cysteine-rich sequence motif, designated LIM. The metal centers in two LIM-domain proteins, designated Cysteine-Rich Protein (CRP) and Cysteine- Rich Intestinal Protein (CRIP) will be studied to determine whether LIM proteins exhibit metal-induced conformational dynamics. A central postulate is that the structure and function of these classes of proteins are affected by the coordination chemistry of the metal centers. We eventually want to determine the role of specific metal ion binding in function. Molecules in these three classes exhibit a wide range of physiological functions from regulation of DNA transcription (ACE1 and AMT1), metal ion buffering (MT), inhibition of neuron outgrowth (GIF), protein-protein interaction (CRP) and perhaps metal transport (CRIP).