Warfarin and vitamin K compete for binding to Phe55 in human VKOR
Warfarin and vitamin K compete for binding to Phe55 in human VKOR
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DOI：
10.1038/nsmb.3338
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发表时间：
2017-01-01
影响因子：
16.8
通讯作者：
Oldenburg, Johannes
中科院分区：
文献类型：
--
作者：
Czogalla, Katrin J.;Biswas, Arijit;Oldenburg, Johannes
维生素K环氧化物还原酶（VKOR）催化维生素K醌和维生素K 2，3-环氧化物的还原，这是维持维生素K依赖性蛋白的γ-羧化所必需的过程。VKOR也是治疗血栓性疾病的华法林的治疗靶点。然而，维生素K减少的结构和功能基础以及华法林抑制的拮抗作用仍然难以捉摸。在这里，我们确定了维生素K和华法林对人VKOR的假定结合位点。通过特定突变残基的偏移剂量-反应曲线验证了预测的华法林结合位点。我们使用CRISPR-Cas9工程化的HEK 293 T细胞来评估VKOR变体的维生素K醌和维生素K 2，3-环氧化物还原酶活性，以表征维生素K萘醌头部和类异戊二烯侧链结合区域。我们的研究结果挑战了非竞争性华法林抑制的流行概念，因为维生素K和华法林共享VKOR上的结合位点，包括Phe 55，一个关键的残基结合底物或抑制剂。
Vitamin K epoxide reductase (VKOR) catalyzes the reduction of vitamin K quinone and vitamin K 2,3-epoxide, a process essential to sustain gamma-carboxylation of vitamin K-dependent proteins. VKOR is also a therapeutic target of warfarin, a treatment for thrombotic disorders. However, the structural and functional basis of vitamin K reduction and the antagonism of warfarin inhibition remain elusive. Here, we identified putative binding sites of both K vitamers and warfarin on human VKOR. The predicted warfarin-binding site was verified by shifted dose-response curves of specified mutated residues. We used CRISPR-Cas9-engineered HEK 293T cells to assess the vitamin K quinone and vitamin K 2,3-epoxide reductase activities of VKOR variants to characterize the vitamin K naphthoquinone head- and isoprenoid side chain-binding regions. Our results challenge the prevailing concept of noncompetitive warfarin inhibition because K vitamers and warfarin share binding sites on VKOR that include Phe55, a key residue binding either the substrate or inhibitor.