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Nicotinamide Adenine Dinucleotides Arrest Photoreduction of Class II DNA Photolyases in FADH ˙ State
Author(s) -
Ignatz Elisabeth,
Geisselbrecht Yann,
Kiontke Stephan,
Essen LarsOliver
Publication year - 2017
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12834
Subject(s) - photolyase , flavin group , chemistry , cofactor , cryptochrome , redox , tryptophan , flavin adenine dinucleotide , electron transfer , flavoprotein , nad+ kinase , photochemistry , electron transport chain , biochemistry , dna , stereochemistry , enzyme , dna repair , amino acid , gene , circadian clock , organic chemistry
Abstract All light‐sensitive members of the photolyase/cryptochrome family rely on FAD as catalytic cofactor. Its activity is regulated by photoreduction, a light‐triggered electron transfer process from a conserved tryptophan triad to the flavin. The stability of the reduced flavin depends on available external electron donors and oxygen. In this study, we show for the class II photolyase of Methanosarcina mazei , Mm CPDII , that it utilizes physiologically relevant redox cofactors NADH and NADPH for the formation of the semiquinoid FAD in a light‐dependent reaction. Using redox‐inert variants Mm CPDII /W388F and Mm CPDII /W360F, we demonstrate that photoreduction by NADH and NADPH requires the class II ‐specific tryptophan cascade of Mm CPDII . Finally, we confirmed that mutations in the tryptophan cascade can be introduced without any substantial structural disturbances by analyzing crystal structures of Mm CPDII /W388F, Mm CPDII /W360F and Mm CPDII /Y345F.