Vitamin K epoxide reductase: homology, active site and catalytic mechanism
Vitamin K epoxide reductase: homology, active site and catalytic mechanism
复制标题
DOI：
10.1016/j.tibs.2004.04.004
复制
发表时间：
2004-06-01
影响因子：
13.8
通讯作者：
Ponting, CP
中科院分区：
文献类型：
--
作者：
Goodstadt, L;Ponting, CP
维生素K环氧化物还原酶（VKOR）回收还原的维生素K，随后用作凝血酶中谷氨酸残基γ-羧化的辅助因子。VKORC 1是VKOR复合物的一个亚基，最近已被证明具有这种活性。在这里，我们表明，VKORC 1是一个大家庭的预测酶，存在于脊椎动物，果蝇，植物，细菌和古细菌的成员。四个半胱氨酸残基和一个残基，这是丝氨酸或苏氨酸，被确定为可能的活性位点残基。在一些植物和细菌同源物中，VKORC 1同源结构域与氧化还原酶的硫氧还蛋白家族的结构域融合。这些可能减少VKORC 1样酶的二硫键作为其催化活性的先决条件。
Vitamin K epoxide reductase (VKOR) recycles reduced vitamin K, which is used subsequently as a co-factor in the gamma-carboxylation of glutamic acid residues in blood coagulation enzymes. VKORC1, a subunit of the VKOR complex, has recently been shown to possess this activity. Here, we show that VKORC1 is a member of a large family of predicted enzymes that are present in vertebrates, Drosophila, plants, bacteria and archaea. Four cysteine residues and one residue, which is either serine or threonine, are identified as likely active-site residues. In some plant and bacterial homologues the VKORC1 homologous domain is fused with domains of the thioredoxin family of oxidoreductases. These might reduce disulfide bonds of VKORC1-like enzymes as a prerequisite for their catalytic activities.