THE STRUCTURE OF COPPER-NITRITE REDUCTASE FROM ACHROMOBACTER CYCLOCLASTES AT 5 PH VALUES, WITH NO2- BOUND AND WITH TYPE-II COPPER DEPLETED
THE STRUCTURE OF COPPER-NITRITE REDUCTASE FROM ACHROMOBACTER CYCLOCLASTES AT 5 PH VALUES, WITH NO2- BOUND AND WITH TYPE-II COPPER DEPLETED
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DOI：
10.1074/jbc.270.46.27458
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发表时间：
1995-11-17
影响因子：
4.8
通讯作者：
TURLEY, S
中科院分区：
文献类型：
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作者：
ADMAN, ET;GODDEN, JW;TURLEY, S
高分辨率的X-射线晶体结构的亚硝酸盐还原酶无色杆菌cycloclastes，为了了解与亚硝酸盐的反应的最佳pH值进行，显示在pH值5.0，5.4，6.0，6.2，和6.8，没有显着的变化发生，除了在II型铜在活性位点的占用。在三聚体的亚基内和亚基之间的广泛的氢键网络保持蛋白质结构的刚性。在II型贫铜结构的结构中，水占据与II型铜的位置相距1.5埃的位置在亚硝酸盐浸泡的晶体中，亚硝酸盐通过其氧与II型铜结合并取代通常与II型铜结合的水，蛋白质的活性位点空腔在一侧明显疏水，在另一侧明显亲水，为产物NO的扩散提供了可能的路径，Asp-98表现出高于其周围环境的热参数值，表明其在穿梭整个反应所需的两个质子中的作用，描述了与铜氧还蛋白的强结构同源性，
High resolution x-ray crystallographic structures of nitrite reductase from Achromobacter cycloclastes, undertaken in order to understand the pH optimum of the reaction with nitrite, show that at pH 5.0, 5.4, 6.0, 6.2, and 6.8, no significant changes occur, other than in the occupancy of the type II copper at the active site. An extensive network of hydrogen bonds, both within and between subunits of the trimer, maintains the rigidity of the protein structure. A water occupies a site similar to 1.5 Angstrom from the site of the type II copper in the structure of the type II copper-depleted structure (at pH 5.4), again with no other significant changes in structure, In nitrite-soaked crystals, nitrite binds via its oxygens to the type II copper and replaces the water normally bound to the type II copper, The active-site cavity of the protein is distinctly hydrophobic on one side and hydrophilic on the other, providing a possible path for diffusion of the product NO, Asp-98 exhibits thermal parameter values higher than its surroundings, suggesting a role in shuttling the two protons necessary for the overall reaction, The strong structural homology with cupredoxins is described,