精制lipoamide脱氢酶的晶体结构固氮菌vinelandii 2.2一项决议。比较与谷胱甘肽还原酶的结构。
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Mattevi Schierbeek AJ,假日工作组
精制lipoamide脱氢酶的晶体结构固氮菌vinelandii 2.2一项决议。比较与谷胱甘肽还原酶的结构。
J杂志。1991年8月20日,220 (4):975 - 94。
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1880807 (在PubMed]
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lipoamide脱氢酶的结构从固氮菌vinelandii精制了分子动力学技术在分辨率2.2 r因子为19.8%。在最后的模型中,理想的均方根偏差是0.02键长和键角3.2度。不对称单元包含两个子单元,每个466氨基酸残基组成的辅基时尚,加上512溶剂分子。最后十个氨基酸残基的链是不可见的电子密度分布,也许他们说的是无序的。所需的操作重叠两个链形成二聚体的旋转180度,没有翻译组件。最后的模型显示了两个独立精制单元非常相似,除了六环位于表面的分子。每个亚基的酶的结构包括四个领域的催化中心位于亚基接口。48-53活性二硫化物桥,是氧化和S伽马3.5 Cys53位于远离碳C-4a异咯嗪环。His450的侧链点对年代的Nε2γCys48,氢连着Glu455的羧酸盐。时尚是绑定在一个扩展的构象和异咯嗪环并不是完全平面的夹角7.3度的蝶啶和苯环第一单元和第二个12.1度。 The overall folding of lipoamide dehydrogenase is very similar to that of glutathione reductase. However, a comparison of the two enzymes, which have only 26% sequence identity, reveals significant conformational differences. These concern the tertiary as well as the quaternary structure of the two molecules. In each subunit of lipoamide dehydrogenase the NAD-binding domain and the interface domain appear to be differently oriented with respect to the FAD-binding domain by 7.1 degrees and 7.8 degrees, respectively. The interface domain contains, in addition, major changes in tertiary structure. Furthermore, the two subunits forming the dimer appear to be shifted with respect to each other by more than 4 A, when the lipoamide dehydrogenase dimer is compared with that of glutathione reductase. In spite of all these changes at the tertiary and quaternary level the active sites of the enzymes, which occur at the dimer interface, appear to be remarkably similar.(ABSTRACT TRUNCATED AT 400 WORDS)