Dynamics and mechanism of DNA repair by a bifunctional cryptochrome.

ABSTRACT: Photolyase and cryptochrome belong to a group of structurally similar flavoproteins but with two distinct functions of DNA repair as a photoenzyme and signal transduction as a photoreceptor, respectively, under blue-light illumination. Here, we studied a recently discovered bifunctional Chlamydomonas reinhardtii cryptochrome (CraCRY) with focus on its repair of UV-induced pyrimidine-pyrimidone (6-4) photoproduct (6-4PP). We used femtosecond spectroscopy and site-directed mutagenesis to map out the critical elementary steps by following the dynamics of initial reactants, various intermediates, and final products. We observed initial direct ultrafast electron tunneling from the hydroquinone flavin cofactor to 6-4PP in 300 ps through an intervening adenine as a mediator, minimizing the

SUBMITTER: Yan L 

PROVIDER: S-EPMC11648919 | biostudies-literature | 2024 Dec

REPOSITORIES: biostudies-literature