Light-activated cryptochrome reacts with molecular oxygen to form a flavin-superoxide radical pair consistent with magnetoreception

J Biol Chem. 2011 Jun 17;286(24):21033-40. doi: 10.1074/jbc.M111.228940. Epub 2011 Apr 5.


Cryptochromes are flavin-based photoreceptors occurring throughout the biological kingdom, which regulate growth and development in plants and are involved in the entrainment of circadian rhythms of both plants and animals. A number of recent theoretical works suggest that cryptochromes might also be the receptors responsible for the sensing of the magnetic field of the earth (e.g. in insects, migratory birds, or migratory fish). Cryptochromes undergo forward light-induced reactions involving electron transfer to excited state flavin to generate radical intermediates, which correlate with biological activity. Here, we give evidence of a mechanism for the reverse reaction, namely dark reoxidation of protein-bound flavin in Arabidopsis thaliana cryptochrome (AtCRY1) by molecular oxygen that involves formation of a spin-correlated FADH(•)-superoxide radical pair. Formation of analogous radical pairs in animal cryptochromes might enable them to function as magnetoreceptors.

Publication types

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

MeSH terms

  • Animals
  • Arabidopsis / metabolism
  • Cryptochromes / chemistry*
  • Drosophila
  • Electrodes
  • Flavins / chemistry*
  • Humans
  • Light
  • Magnetics
  • Oxygen / chemistry
  • Oxygen Consumption
  • Reactive Oxygen Species
  • Signal Transduction
  • Spectrophotometry, Ultraviolet / methods
  • Superoxides / chemistry*


  • Cryptochromes
  • Flavins
  • Reactive Oxygen Species
  • Superoxides
  • Oxygen