Boyington J C, Gladyshev V N, Khangulov S V, Stadtman T C, Sun P D
Laboratory of Molecular Structure, National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH), Rockville, MD 20852, USA.
Science. 1997 Feb 28;275(5304):1305-8. doi: 10.1126/science.275.5304.1305.
Formate dehydrogenase H from Escherichia coli contains selenocysteine (SeCys), molybdenum, two molybdopterin guanine dinucleotide (MGD) cofactors, and an Fe4S4 cluster at the active site and catalyzes the two-electron oxidation of formate to carbon dioxide. The crystal structures of the oxidized [Mo(VI), Fe4S4(ox)] form of formate dehydrogenase H (with and without bound inhibitor) and the reduced [Mo(IV), Fe4S4(red)] form have been determined, revealing a four-domain alphabeta structure with the molybdenum directly coordinated to selenium and both MGD cofactors. These structures suggest a reaction mechanism that directly involves SeCys140 and His141 in proton abstraction and the molybdenum, molybdopterin, Lys44, and the Fe4S4 cluster in electron transfer.
来自大肠杆菌的甲酸脱氢酶H在活性位点含有硒代半胱氨酸（SeCys）、钼、两个钼蝶呤鸟嘌呤二核苷酸（MGD）辅因子和一个Fe4S4簇，并催化甲酸双电子氧化为二氧化碳。已确定甲酸脱氢酶H的氧化态[Mo(VI), Fe4S4(ox)]形式（有和没有结合抑制剂）和还原态[Mo(IV), Fe4S4(red)]形式的晶体结构，揭示了一种四结构域的αβ结构，其中钼直接与硒以及两个MGD辅因子配位。这些结构表明了一种反应机制，该机制直接涉及SeCys140和His141参与质子抽取，以及钼、钼蝶呤、Lys44和Fe4S4簇参与电子转移。
