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          Institute: MPI für medizinische Forschung     Collection: jahrbuch_2011_archival     Display Documents



ID: 597780.0, MPI für medizinische Forschung / jahrbuch_2011_archival
Neutral Histidine and Photoinduced Electron Transfer in DNA Photolyases
Translation of Title:Neutral Histidine and Photoinduced Electron Transfer in DNA Photolyases
Authors:Domratcheva, Tatiana
Language:English
Date of Publication (YYYY-MM-DD):2011-11-16
Title of Journal:Journal of the American Chemical Society
Journal Abbrev.:Journal of the American Chemical Society
Volume:133
Issue / Number:45
Start Page:18172
End Page:18182
Review Status:Peer-review
Audience:Experts Only
Intended Educational Use:No
Abstract / Description:The two major UV−induced DNA lesions, the cyclobutane pyrimidine dimers (CPD) and (6−4) pyrimidine−pyrimidone photoproducts, can be repaired by the light−activated enzymes CPD and (6−4) photolyases, respectively. It is a long−standing question how the two classes of photolyases with alike molecular structure are capable of reversing the two chemically different DNA photoproducts. In both photolyases the repair reaction is initiated by photoinduced electron transfer from the hydroquinone−anion part of the flavin adenine dinucleotide (FADH−) cofactor to the photoproduct. Here, the state−of−the−art XMCQDPT2−CASSCF approach was employed to compute the excitation spectra of the respective active site models. It is found that protonation of His365 in the presence of the hydroquinone−anion electron donor causes spontaneous, as opposed to photoinduced, coupled proton and electron transfer to the (6−4) photoproduct. The resulting neutralized biradical, containing the neutral semiquinone and the N3'−protonated (6−4) photoproduct neutral radical, corresponds to the lowest energy electronic ground−state minimum. The high electron affinity of the N3'−protonated (6−4) photoproduct underlines this finding. Thus, it is anticipated that the (6−4) photoproduct repair is assisted by His365 in its neutral form, which is in contrast to the repair mechanisms proposed in the literature. The repair via hydroxyl group transfer assisted by neutral His365 is considered. The repair involves the 5'base radical anion of the (6−4) photoproduct which in terms of electronic structure is similar to the CPD radical anion. A unified model of the CPD and (6−4) photoproduct repair is proposed
External Publication Status:published
Document Type:Article
Communicated by:Wulf Kaiser
Affiliations:MPI für medizinische Forschung/Abteilung Biomolekulare Mechanismen
MPI für medizinische Forschung/Abteilung Biomolekulare Mechanismen/Computational Photobiology
Identifiers:LOCALID:7730
URI:http%3A%2F%2Fpubs.acs.org%2Fdoi%2Fpdfplus%2F10.102...
URI:http%3A%2F%2Fpubs.acs.org%2Fdoi%2Ffull%2F10.1021%2...
URI:http%3A%2F%2Fpubs.acs.org%2Fdoi%2Fabs%2F10.1021%2F...
DOI:10.1021%2Fja203964d
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