Crystal structure and mechanism of CO dehydrogenase, a molybdo iron-sulfur flavoprotein containing S-selanylcysteine
Crystal structure and mechanism of CO dehydrogenase, a molybdo iron-sulfur flavoprotein containing S-selanylcysteine
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DOI：
10.1073/pnas.96.16.8884
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发表时间：
1999-08-03
影响因子：
11.1
通讯作者：
Huber, R
中科院分区：
文献类型：
--
作者：
Dobbek, H;Gremer, L;Huber, R
来自需氧细菌 Oligotropa carboxidovorans 的 CO 脱氢酶催化 CO 与 H2O 的氧化，产生 CO2、两个电子和两个 H+。其空气氧化形式的晶体结构已确定为2.2 A。该酶的活性位点含有钼和三个氧配体、钼蝶呤胞嘧啶二核苷酸和S-硒酰半胱氨酸，将电子传递到由两种类型的[2Fe-2S]簇和黄素-腺嘌呤二核苷酸组成的分子内电子传递链，CO脱氢酶由88.7-kDa组成钼蛋白 (L)、30.2 kDa 黄素蛋白 (M) 和 17.8 kDa 铁硫蛋白 (S)。它被组织为 LMS 异源三聚体的二聚体，并且在许多方面（但不是全部）类似于黄嘌呤脱氢酶/氧化酶。提出了一种基于结合有自杀底物氰化物的结构的机制，并显示了 S-硒酰半胱氨酸对于催化反应的必要性。
CO dehydrogenase from the aerobic bacterium Oligotropha carboxidovorans catalyzes the oxidation of CO with H2O, yielding CO2, two electrons, and two H+. Its crystal structure in the air-oxidized form has been determined to 2.2 A. The active site of the enzyme, which contains molybdenum with three oxygen ligands, molybdopterincytosine dinucleotide and S-selanylcysteine, delivers the electrons to an intramolecular electron transport chain composed of two types of [2Fe-2S] clusters and flavin-adenine dinucleotide, CO dehydrogenase is composed of an 88.7-kDa molybdoprotein (L), a 30.2-kDa flavoprotein (M), and a 17.8-kDa iron-sulfur protein (S). It is organized as a dimer of LMS heterotrimers and resembles xanthine dehydrogenase/oxidase in many, but not all, aspects. A mechanism based on a structure with the bound suicide-substrate cyanide is suggested and displays the necessity of S-selanylcysteine for the catalyzed reaction.