Dobbek H, Gremer L, Meyer O, Huber R
Max-Planck-Institut für Biochemie, Abteilung Strukturforschung, D-82152 Martinsried, Germany.
Proc Natl Acad Sci U S A. 1999 Aug 3;96(16):8884-9. doi: 10.1073/pnas.96.16.8884.
CO dehydrogenase from the aerobic bacterium Oligotropha carboxidovorans catalyzes the oxidation of CO with H(2)O, yielding CO(2), 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, molybdopterin-cytosine 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.
来自需氧细菌食羧寡养菌的一氧化碳脱氢酶催化一氧化碳与水的氧化反应，生成二氧化碳、两个电子和两个氢离子。已确定其空气氧化形式的晶体结构分辨率为2.2埃。该酶的活性位点含有带有三个氧配体的钼、钼蝶呤 - 胞嘧啶二核苷酸和S - 硒代半胱氨酸，它将电子传递至由两种类型的[2Fe - 2S]簇和黄素腺嘌呤二核苷酸组成的分子内电子传递链。一氧化碳脱氢酶由一个88.7 kDa的钼蛋白（L）、一个30.2 kDa的黄素蛋白（M）和一个17.8 kDa的铁硫蛋白（S）组成。它以LMS异源三聚体的二聚体形式存在，在许多但并非所有方面类似于黄嘌呤脱氢酶/氧化酶。提出了一种基于与结合的自杀底物氰化物的结构的机制，并展示了S - 硒代半胱氨酸对于催化反应的必要性。
