METAL CHELATION IN PROTEINS WITH POLYMETALLIC CLUSTERS

重点放在形成金属硫酸盐的富含半胱氨酸的蛋白质上。 多金属团簇。这一类的一个范例是金属硫蛋白(MT)。 锌(II)和锌离子诱导了具有不同性质的多金属团簇 铜(I)离子。一个目标是确定结构的大小 MT中的重组取决于形成的簇的类型。一秒钟 目的是确定相似的星系团结构是否会改变 这些蛋白质的第三折叠和功能。三类分子 将会被研究。首先，一种新的金属硫蛋白与 将对阿尔茨海默氏症进行调查。MT，指定为GIF 生长抑制因子抑制树枝晶形成的活性 阿尔茨海默病脑提取物诱导的神经元。错综复杂的外围地带 阿尔茨海默病特有的神经元可能与 阿尔茨海默病患者脑组织中低浓度的GIF。我们建议 确定哪种金属构象的GIF活性的实验 逆转阿尔茨海默氏症提取物诱导神经元增殖。一个 提出了一系列实验来映射GIF负责的部分 用于活动。我们计划将GIF中的金属团簇表征为 确定MT和GIF中的序列差异是否会影响属性 多金属团簇。第二类蛋白质包括两种 真菌转录因子。ACE和AMT1。CU(I)绑定到ACE！和 AMT1激活MT基因转录激活因子 酿酒酵母和光滑假丝酵母。我们建议 这两种化合物中铜(I)硫酸盐多金属簇合物的表征 蛋白质构象。CuACE1和CuAMT1的DNA结合位点将是 以阐明其结构为特征的 转录活性CuAMT1/DNA复合体。第三类是 富含半胱氨酸的序列基序，命名为LIM。金属中心分成两半 LIM结构域蛋白，命名为富含半胱氨酸的蛋白(CRP)和半胱氨酸- 将研究富含肠道蛋白(CRIP)以确定LIM是否 蛋白质表现出金属诱导的构象动力学。一个中环 假设这些蛋白质的结构和功能 受到金属中心配位化学的影响。我们 最终想要确定特定的金属离子结合在 功能。这三类分子表现出广泛的 DNA转录调控的生理功能(ACE1和 AMT1)、金属离子缓冲(MT)、抑制神经元生长(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).