title: NMR structure of an ethylene interstrand cross-linked DNA which mimics the lesion formed by 1,3-bis(2-chloroethyl)-1-nitrosourea.
abstract: The bisalkylating agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), used in cancer chemotherapy to hinder cellular proliferation, forms lethal interstrand cross-links (ICLs) in DNA. BCNU generates an ethylene linkage connecting the two DNA strands at the N1 atom of 2'-deoxyguanosine and N3 atom of 2'-deoxycytidine, which is a synthetically challenging probe to prepare. To this end, an ICL duplex linking the N1 atom of 2'-deoxyinosine to the N3 atom of thymidine via an ethylene linker was devised as a mimic. We have solved the structure of this ICL duplex by a combination of molecular dynamics and high-field NMR experiments. The ethylene linker is well-accommodated in the duplex with minimal global and local perturbations relative to the unmodified duplex. These results may account for the substantial stabilization of the ICL duplex observed by UV thermal denaturation experiments and provides structural insights of a probe that may be useful for DNA repair studies.
authors.affiliation: Department of Chemistry & Biochemistry, Concordia University, Montréal, QC H4B 1R6 (Canada).
authors.forename: Derek K
authors.initials: DK
authors.lastname: O'Flaherty
authors.forename: Alexey Y
authors.initials: AY
authors.lastname: Denisov
authors.forename: Anne M
authors.initials: AM
authors.lastname: Noronha
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Wilds
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000138:chemical synthesis* / Q000494:pharmacology*; D002330:Carmustine / Q000494:pharmacology*; D003432:Cross-Linking Reagents; D004247:DNA / Q000737:chemistry* / Q000494:pharmacology*; D005030:Ethylenes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D013816:Thermodynamics
chemical_list: D018906:Antineoplastic Agents, Alkylating; D003432:Cross-Linking Reagents; D005030:Ethylenes; D004247:DNA; D002330:Carmustine
keywords: DNA; DNA damage; DNA structures; NMR spectroscopy; bioorganic chemistry