title: Synthesis and characterization of DNA duplexes containing an N3T-ethyl-N3T interstrand crosslink in opposite orientations.
abstract: DNA duplexes containing an ethyl interstrand crosslink that bridges the N3 atoms of thymidines on the opposite strands have been synthesized using an approach that combines conventional solid phase oligonucleotide synthesis and the selective removal of protecting groups of a crosslinked thymidine dimer. This approach allows for the assembly of a crosslinked duplex directly on the solid support. Duplexes that contain a N3T-ethyl-N3T interstrand crosslink in a staggered orientation at either a -TA- or -AT-step in a duplex have been prepared. When placed in an -AT- step of a duplex the effect was stabilizing relative to the non-crosslinked control duplex (deltaTm= +24 degrees C) and this crosslinked duplex was found to efficiently form multimers in the presence of T4 ligase. In the case of the -TA- crosslinked duplex the stabilizing effect was less pronounced (deltaT.= +6 degrees C) and likewise did not undergo self ligation under identical conditions. Molecular modeling studies suggested that the -AT- containing lesion had little deviation in structure relative to the non-crosslinked duplex DNA control, whereas the -TA- crosslinked duplex exhibited significant buckling of the base pairs flanking the lesion.
authors.affiliation: Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Wilds
authors.forename: Anne M
authors.initials: AM
authors.lastname: Noronha
authors.forename: Sebastien
authors.initials: S
authors.lastname: Robidoux
authors.forename: Paul S
authors.initials: PS
authors.lastname: Miller
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D001483:Base Sequence; D002942:Circular Dichroism; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004247:DNA / Q000737:chemistry; D019281:Dimerization; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009692:Nucleic Acid Heteroduplexes; D010766:Phosphorylation; D013696:Temperature; D013816:Thermodynamics; D013936:Thymidine / Q000737:chemistry
chemical_list: D000477:Alkylating Agents; D000970:Antineoplastic Agents; D003432:Cross-Linking Reagents; D008024:Ligands; D009692:Nucleic Acid Heteroduplexes; D004247:DNA; D013936:Thymidine