Single Amino Acid Substitution Reveals Latent Photolyase Activity in Arabidopsis cry1


  • This work was supported by grants from Human Frontiers RGP0045/2008-C and the National Science Foundation 33701 to M. Ahmad and the Deutsche Forschungsgemeinschaft FOR 526 to R. Bittl (Bi464-8), J. Heberle, and T. Kottke. We thank M. Narayanan and R. Stanley for assistance and helpful discussions in photoreactivation assays, P. Mueller for help with manuscript preparation, and members of the UR5 plant science laboratory at Université de Paris for assistance with experimental work and facilities.


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A quick switch: A single amino acid substitution at a conserved residue (D396N) of Arabidopsis cryptochrome-1 (Atcry1) confers single-stranded DNA repair activity in vitro, conferring photolyase activity onto the cryptochrome (see graph). The mutant protein undergoes photoreduction of flavin to the fully reduced anionic form, similar to photolyases and unlike wild-type cryptochromes.