title: Coexistence of Different Electron-Transfer Mechanisms in the DNA Repair Process by Photolyase.
abstract: DNA photolyase has been the topic of extensive studies due to its important role of repairing photodamaged DNA, and its unique feature of using light as an energy source. A crucial step in the repair by DNA photolyase is the forward electron transfer from its cofactor (FADH(-) ) to the damaged DNA, and the detailed mechanism of this process has been controversial. In the present study, we examine the forward electron transfer in DNA photolyase by carrying out high-level ab initio calculations in combination with a quantum mechanical/molecular mechanical (QM/MM) approach, and by measuring fluorescence emission spectra at low temperature. On the basis of these computational and experimental results, we demonstrate that multiple decay pathways exist in DNA photolyase depending on the wavelength at excitation and the subsequent transition. This implies that the forward electron transfer in DNA photolyase occurs not only by superexchange mechanism but also by sequential electron transfer.
authors.affiliation: Department of Chemistry, Temple University, Philadelphia, Pennsylvania, 19122, USA. tuf65152@temple.edu.
authors.forename: Wook
authors.initials: W
authors.lastname: Lee
authors.affiliation: Teva Pharmaceuticals USA, Inc, 145 Brandywine Pkwy, West Chester, Pennsylvania, 19380, USA.
authors.forename: Goutham
authors.initials: G
authors.lastname: Kodali
authors.affiliation: Department of Chemistry, Temple University, Philadelphia, Pennsylvania, 19122, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Stanley
authors.affiliation: Department of Chemistry, Temple University, Philadelphia, Pennsylvania, 19122, USA.
authors.forename: Spiridoula
authors.initials: S
authors.lastname: Matsika
mesh_terms: D004249:DNA Damage; D004260:DNA Repair / Q000502:physiology*; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000737:chemistry* / Q000378:metabolism*; D004579:Electron Transport; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry* / Q000378:metabolism; D010777:Photochemistry
chemical_list: D005182:Flavin-Adenine Dinucleotide; D004255:Deoxyribodipyrimidine Photo-Lyase
keywords: QM/MM; ab initio calculations; electron transfer; electronic coupling; photolyase