title: Rearrangement of a 1,3-trans-[Pt(NH3)2[(GXG)-N7G,N7G]] intrastrand cross-link into interstrand cross-links within RNA duplexes.
abstract: The cross-linking reaction described previously in the DNA and 2'-O-methyl RNA series is extended to RNA duplexes. A 17mer single-stranded RNA containing the 1,3-trans-[Pt(NH3)2[(GAG)-N7G,N7G]] intrastrand chelate, named G*AG* (* indicating a platinated base) gives, upon pairing with the complementary RNA strand, the G*AG/CUC* interstrand cross-link. The rate of the reaction in 200 mM NaClO4 is similar to that observed for DNA-RNA duplexes. It depends on the added Na+ or Mg2+ cation and on its concentration. RNA duplexes containing GA/GA or AG/AG tandem mismatches in the rearrangement triplet core were also studied. The major interstrand cross-links, G*AG/CGA* and G*AG/AGC*, are accompanied by a minor one involving the central G of the CGA or AGC complementary sequence G*AG/CG*A and G*AG/AG*C. In 200 mM NaClO4, the G*A/GA tandem mismatch does not modify the rate of the cross-linking rearrangement whereas the AG*/AG mismatch slows it down by a factor of four. Our results reflect the predominance of the local structure of the rearrangement core over the nucleophility of the cross-linking base. They also show that the reaction could be used to trap tertiary structures of naturally occurring RNAs, including those with the commonly encountered GA/GA mismatch.
authors.affiliation: Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601, Université René Descartes, 45 rue des Saints-Pères, 75270 Paris cedex 06, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Escaffre
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Chottard
authors.forename: Sophie
authors.initials: S
authors.lastname: Bombard
mesh_terms: D020029:Base Pairing; D001483:Base Sequence; D001665:Binding Sites; D003432:Cross-Linking Reagents / Q000737:chemistry; D018736:DNA Adducts / Q000737:chemistry; D007700:Kinetics; D008957:Models, Genetic; D009692:Nucleic Acid Heteroduplexes / Q000737:chemistry*; D009944:Organoplatinum Compounds / Q000737:chemistry* / Q000378:metabolism; D012313:RNA / Q000737:chemistry*; D012265:Ribonucleotides / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D018736:DNA Adducts; D009692:Nucleic Acid Heteroduplexes; D009944:Organoplatinum Compounds; D012265:Ribonucleotides; D012313:RNA