title: Repair of DNA Dewar photoproduct to (6-4) photoproduct in (6-4) photolyase.
abstract: Dewar photoproduct (Dewar PP) is the valence isomer of (6-4) photoproduct ((6-4)PP) in photodamaged DNA. Compared to the extensive studied CPD photoproducts, the underlying repair mechanisms for the (6-4)PP, and especially for the Dewar PP, are not well-established to date. In this paper, the repair mechanism of DNA Dewar photoproduct T(dew)C in (6-4) photolyase was elucidated using hybrid density functional theory. Our results showed that, during the repair process, the T(dew)C has to isomerize to T(6-4)C photolesion first via direct C6'-N3' bond cleavage facilitated by electron injection. This isomerization mechanism is energetically much more efficient than other possible rearrangement pathways. The calculations provide a theoretical interpretation to recent experimental observations.
authors.affiliation: Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden.
authors.forename: Yue-Jie
authors.initials: YJ
authors.lastname: Ai
authors.forename: Rong-Zhen
authors.initials: RZ
authors.lastname: Liao
authors.forename: Shi-Lu
authors.initials: SL
authors.lastname: Chen
authors.forename: Wei-Jie
authors.initials: WJ
authors.lastname: Hua
authors.forename: Wei-Hai
authors.initials: WH
authors.lastname: Fang
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
mesh_terms: D004247:DNA / Q000378:metabolism*; D018736:DNA Adducts / Q000737:chemistry*; D004260:DNA Repair; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000378:metabolism*; D007536:Isomerism; D008962:Models, Theoretical
chemical_list: D018736:DNA Adducts; D004247:DNA; D004255:Deoxyribodipyrimidine Photo-Lyase