Structural basis of antagonizing the vitamin K catalytic cycle for anticoagulation

Science. 2021 Jan 1;371(6524):eabc5667. doi: 10.1126/science.abc5667. Epub 2020 Nov 5.


Vitamin K antagonists are widely used anticoagulants that target vitamin K epoxide reductases (VKOR), a family of integral membrane enzymes. To elucidate their catalytic cycle and inhibitory mechanism, we report 11 x-ray crystal structures of human VKOR and pufferfish VKOR-like, with substrates and antagonists in different redox states. Substrates entering the active site in a partially oxidized state form cysteine adducts that induce an open-to-closed conformational change, triggering reduction. Binding and catalysis are facilitated by hydrogen-bonding interactions in a hydrophobic pocket. The antagonists bind specifically to the same hydrogen-bonding residues and induce a similar closed conformation. Thus, vitamin K antagonists act through mimicking the key interactions and conformational changes required for the VKOR catalytic cycle.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Anticoagulants / pharmacology*
  • Biocatalysis
  • Blood Coagulation / drug effects*
  • Catalytic Domain
  • Crystallography, X-Ray
  • Cysteine / chemistry
  • Humans
  • Hydrogen Bonding
  • Hydrophobic and Hydrophilic Interactions
  • Oxidation-Reduction
  • Protein Structure, Secondary
  • Takifugu
  • Vitamin K / antagonists & inhibitors*
  • Vitamin K Epoxide Reductases / chemistry*


  • Anticoagulants
  • Vitamin K
  • VKORC1 protein, human
  • Vitamin K Epoxide Reductases
  • Cysteine