title: DNA bending and unwinding due to the major 1,2-GG intrastrand cross-link formed by antitumor cis-diamminedichloroplatinum(II) are flanking-base independent.
abstract: Antitumor cisplatin [cis-diamminedichloroplatinum(II)] forms on DNA predominantly intrastrand cross-links between neighboring purine residues. Several discoveries suggested that the toxicity of cisplatin originated from these lesions. The formation of 1,2-GG intrastrand cross-link of cisplatin leads to marked conformational alterations in DNA including a directional, rigid bend toward the major groove and local unwinding. These altered structures attract various cellular proteins. This phenomenon has been postulated to mediate antitumor properties of cisplatin. Importantly, the binding affinity of several proteins that specifically recognize 1,2-GG intrastrand cross-link to platinated DNA is modulated by the nature of the base pairs that immediately flank the platinated d(GpG) site. However, the influence of sequence context on DNA bending and unwinding due to the formation of the 1,2-GG intrastrand cross-link has not been extensively investigated. In the present study we have employed electrophoretic retardation (phasing) assay to analyze bending and unwinding induced by the single, site-specific 1,2-GG intrastrand cross-link immediately flanked by various bases formed by cisplatin in nine oligodeoxyribonucleotide duplexes. The results indicate that bending and unwinding of DNA as a consequence of the formation of the major adduct of cisplatin is, in the first approximation, independent of the base pairs flanking the platinated d(GpG) site.
authors.affiliation: Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, CZ-61265 Brno, Czech Republic.
authors.forename: Kristyna
authors.initials: K
authors.lastname: Stehlikova
authors.forename: Hana
authors.initials: H
authors.lastname: Kostrhunova
authors.forename: Jana
authors.initials: J
authors.lastname: Kasparkova
authors.forename: Viktor
authors.initials: V
authors.lastname: Brabec
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D001483:Base Sequence; D002945:Cisplatin / Q000737:chemistry / Q000494:pharmacology*; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D018736:DNA Adducts; D006151:Guanosine / Q000737:chemistry; D009690:Nucleic Acid Conformation / Q000187:drug effects; D009841:Oligonucleotides / Q000737:chemistry / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D018736:DNA Adducts; D009841:Oligonucleotides; D006151:Guanosine; D004247:DNA; D002945:Cisplatin