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Curr Opin Struct Biol. 2010 Dec;20(6):693-701. doi: 10.1016/j.sbi.2010.07.003. Epub 2010 Aug 10.

Reaction mechanisms of DNA photolyase.

Author information

1
CEA, IBITECS, Laboratoire de Photocatalyse et Biohydrogène, 91191 Gif-sur-Yvette, France. klaus.brettel@cea.fr

Abstract

DNA photolyase uses visible light and a fully reduced flavin cofactor FADH(-) to repair major UV-induced lesions in DNA, the cyclobutane pyrimidine dimers (CPDs). Electron transfer from photoexcited FADH(-) to CPD, splitting of the two intradimer bonds, and back electron transfer to the transiently formed flavin radical FADH° occur in overall 1ns. Whereas the kinetics of FADH° was resolved, the DNA-based intermediates escaped unambiguous detection yet. Another light reaction, named photoactivation, reduces catalytically inactive FADH° to FADH(-) without implication of DNA. It involves electron hopping along a chain of three tryptophan residues in 30ps, as elucidated in detail by transient absorption spectroscopy. The same triple tryptophan chain is found in cryptochrome blue-light photoreceptors and may be involved in their primary photoreaction.

PMID:
20705454
DOI:
10.1016/j.sbi.2010.07.003
[Indexed for MEDLINE]

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