title: Nucleotide excision repair of chemically stabilized analogues of DNA interstrand cross-links produced from oxidized abasic sites.
abstract: Nucleotide excision repair is a primary pathway in cells for coping with DNA interstrand cross-links (ICLs). Recently, C4'-oxidized (C4-AP) and C5'-oxidized abasic sites (DOB) that are produced following hydrogen atom abstraction from the DNA backbone were found to produce ICLs. Because some of the ICLs derived from C4-AP and DOB are too unstable to characterize in biochemical processes, chemically stable analogues were synthesized [Ghosh, S., and Greenberg, M. M. (2014) J. Org. Chem. 79, 5948-5957]. UvrABC incision of DNA substrates containing stabilized analogues of the ICLs derived from C4-AP and DOB was examined. The incision pattern for the ICL related to the C4'-oxidized abasic site was typical for UvrABC substrates. UvrABC cleaved both strands of the substrate containing the C4-AP ICL analogue, but it was a poor substrate. UvrABC incised <30% of the C4-AP ICL analogue over an 8 h period, raising the possibility that this cross-link will be inefficiently repaired in cells. Furthermore, double-strand breaks were not detected upon incision of an internally labeled hairpin substrate containing the C4-AP ICL analogue. UvrABC incised the stabilized analogue of the DOB ICL more efficiently (~20% in 1 h). Furthermore, the incision pattern was unique, and the cross-linked substrate was converted into a single product, a double-strand break. The template strand was exclusively incised on the template strand on the 3'-side of the cross-linked dA. Although the outcomes of the interaction between UvrABC and these two cross-linked substrates are different from one another, they provide additional examples of how seemingly simple lesions (C4-AP and DOB) can potentially exert significant deleterious effects on biochemical processes.
authors.affiliation: Department of Chemistry, Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States.
authors.forename: Souradyuti
authors.initials: S
authors.lastname: Ghosh
authors.forename: Marc M
authors.initials: MM
authors.lastname: Greenberg
mesh_terms: D001483:Base Sequence; D003432:Cross-Linking Reagents / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D004260:DNA Repair; D004706:Endodeoxyribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction
chemical_list: D003432:Cross-Linking Reagents; D029968:Escherichia coli Proteins; D004247:DNA; D004706:Endodeoxyribonucleases; C036385:endodeoxyribonuclease uvrABC