精致的结构从大肠杆菌碱性磷酸酶2.8一项决议。
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Sowadski JM, Handschumacher医学博士没吃嗯,官员培养英航,Wyckoff称HW
精致的结构从大肠杆菌碱性磷酸酶2.8一项决议。
J杂志。1985年11月20日,186(2):417 - 33所示。
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3910843 (在PubMed]
- 文摘
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从大肠杆菌碱性磷酸酶的结构决定2.8决议。多个同形替换二聚体的电子密度图3.4是大大提高了溶剂分子对称平均和压扁。从这些地图,多肽链的二聚体是用发布的氨基酸序列构建的。立体化学的约束最小二乘优化模型对本地数据,从数据和扩展步骤3.4 2.8决议,继续最后一个整体晶体R因子为0.256。碱性phosphatase-phosphomonoester水解酶(EC 3.1.3.1)是一种金属酶,形成了自身二聚体和两个活性中心32。亚基的多肽折叠的拓扑结构是蛋白质的α/β类的。尽管总体相似之处与其他蛋白质α/β折叠,碱性磷酸酶没有绑定裂特征形成的羧基端平行板,而是一个活跃的口袋里,它包含一组三个功能金属站点位于中央ten-stranded表下飞机。这种活性口袋附近的四个链和氨基酸的羧基末端反平行的链,平面之间的表和两个螺旋在同一侧。碱性磷酸酶是一种非特异性磷酸单酯酶,水解磷酸小phosphomonoesters以及末端的DNA。可访问性的计算基于酶的精制坐标显示活性口袋勉强适应无机磷酸盐。 Thus, the alcoholic or phenolic portion of the substrate would have to be exposed on the surface of the enzyme. Two metal sites, M1 and M2, 3.9 A apart, are occupied by zinc. The third site, M3, 5 A from site M2 and 7 A from site M1, is occupied by magnesium or, in the absence of magnesium, by zinc. As with other zinc-containing enzymes, histidine residues are ligands to zinc site M1 (three) and to zinc site M2 (one). Ligand assignment and metal preference indicate that the crystallographically found metal sites M1, M2 and M3 correspond to the spectroscopically deduced metal sites A, B and C, respectively. Arsenate, a product analog and enzyme inhibitor, binds between Ser102 and zinc sites M1 and M2. The position of the guanidinium group of Arg 166 is within hydrogen-bonding distance from the arsenate site.(ABSTRACT TRUNCATED AT 400 WORDS)