假单胞菌的精致的水晶结构putida lipoamide脱氢酶与NAD + 2.45一项决议。
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Mattevi, Obmolova G, Sokatch JR Betzel C,假日工作组
假单胞菌的精致的水晶结构putida lipoamide脱氢酶与NAD + 2.45一项决议。
蛋白质。1992年8月,13 (4):336 - 51。
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1325638 (在PubMed]
- 文摘
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的三维结构的三个lipoamide脱氢酶发生在假单胞菌putida, LipDH Val, 2.45决议决定。斜方晶系的晶体,生长在NAD + 20毫米,包含458残留不对称单位。晶体二倍轴生成二聚体在溶液中观察到。18216年最后一个晶体r因子是21.8%独特的反射和3452个蛋白质原子组成的一个模型,189溶剂分子和44 NAD +原子,而整体b因子异常高:47 A2。LipDH Val的结构揭示了构象的c端残留“返回”折叠成公认的lipoamide绑定。糖已经被证明是重要的活动由定点诱变。然而,糖基的催化地基本药物残留的距离非常大,超过6,糖基的精确作用仍然需要阐明。在这个晶体形式LipDH Val每单元包含一个NAD +分子。其adenine-ribose一部分占据了一个类似的地位在谷胱甘肽还原酶的结构。然而,nicotinamide-ribose一半是远离它的预期位置附近的异咯嗪环和点的解决方案。 Comparison of LipDH Val with Azotobacter vinelandii lipoamide dehydrogenase yields an rms difference of 1.6 A for 440 well defined C alpha atoms per subunit. Comparing LipDH Val with glutathione reductase shows large differences in the tertiary and quaternary structure of the two enzymes. For instance, the two subunits in the dimer are shifted by 6 A with respect to each other. So, LipDH Val confirms the surprising differences in molecular architecture between glutathione reductase and lipoamide dehydrogenase, which were already observed in Azotobacter vinelandii LipDH. This is the more remarkable since the active sites are located at the subunit interface and are virtually identical in all three enzymes.