Active site geometry and substrate recognition of the molybdenum hydroxylase quinoline 2-oxidoreductase
Active site geometry and substrate recognition of the molybdenum hydroxylase quinoline 2-oxidoreductase
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DOI：
10.1016/j.str.2004.05.014
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发表时间：
2004-08-01
期刊：
影响因子：
5.7
通讯作者：
Dobbek, H
中科院分区：
文献类型：
--
作者：
Bonin, I;Martins, BM;Dobbek, H
土壤细菌恶臭假单胞菌86使用喹啉作为唯一的碳和能量来源。喹啉2-氧化还原酶（Qor）催化喹啉转化为2-氧代-1，2-二氢喹啉的第一个代谢步骤。Qor是钼羟化酶的成员。钼离子是由两个烯-二硫醇硫原子，两个氧代配体，和催化关键的硫代配体，其在活性位点的位置是有争议的协调。Qor的1.8埃分辨率的晶体结构表明，硫代配体占据了钼离子的赤道位置。QOR与别嘌呤醇抑制的黄嘌呤脱氢酶从Rhodobacter capsulatus的结构比较允许直接洞察底物识别和鉴定推定的催化残基的机制。分析活性位点蛋白变体QorE 743 V和QorE 743 D以评估E743的催化作用。
The soil bacterium Pseudomonas putida 86 uses quinoline as a sole source of carbon and energy. Quinoline 2-oxidoreductase (Qor) catalyzes the first metabolic step converting quinoline to 2-oxo-1,2-dihydroquinoline. Qor is a member of the molybdenum hydroxylases. The molybdenum ion is coordinated by two ene-dithiolate sulfur atoms, two oxo-ligands, and a catalytically crucial sulfido-ligand, whose position in the active site was controversial. The 1.8 Angstrom resolution crystal structure of Qor indicates that the sulfido-ligand occupies the equatorial position at the molybdenum ion. The structural comparison of Qor with the allopurinol-inhibited xanthine dehydrogenase from Rhodobacter capsulatus allows direct insight into the mechanism of substrate recognition and the identification of putative catalytic residues. The active site protein variants QorE743V and QorE743D were analyzed to assess the catalytic role of E743.