title: Spectroscopic characterization of interstrand carbinolamine cross-links formed in the 5'-CpG-3' sequence by the acrolein-derived gamma-OH-1,N2-propano-2'-deoxyguanosine DNA adduct.
abstract: The interstrand N2,N2-dG DNA cross-linking chemistry of the acrolein-derived gamma-OH-1,N2-propanodeoxyguanosine (gamma-OH-PdG) adduct in the 5'-CpG-3' sequence was monitored within a dodecamer duplex by NMR spectroscopy, in situ, using a series of site-specific 13C- and 15N-edited experiments. At equilibrium 40% of the DNA was cross-linked, with the carbinolamine form of the cross-link predominating. The cross-link existed in equilibrium with the non-crosslinked N2-(3-oxo-propyl)-dG aldehyde and its geminal diol hydrate. The ratio of aldehyde/diol increased at higher temperatures. The 1,N2-dG cyclic adduct was not detected. Molecular modeling suggested that the carbinolamine linkage should be capable of maintaining Watson-Crick hydrogen bonding at both of the tandem C x G base pairs. In contrast, dehydration of the carbinolamine cross-link to an imine (Schiff base) cross-link, or cyclization of the latter to form a pyrimidopurinone cross-link, was predicted to require disruption of Watson-Crick hydrogen bonding at one or both of the tandem cross-linked C x G base pairs. When the gamma-OH-PdG adduct contained within the 5'-CpG-3' sequence was instead annealed into duplex DNA opposite T, a mixture of the 1,N2-dG cyclic adduct, the aldehyde, and the diol, but no cross-link, was observed. With this mismatched duplex, reaction with the tetrapeptide KWKK formed DNA-peptide cross-links efficiently. When annealed opposite dA, gamma-OH-PdG remained as the 1,N2-dG cyclic adduct although transient epimerization was detected by trapping with the peptide KWKK. The results provide a rationale for the stability of interstrand cross-links formed by acrolein and perhaps other alpha,beta-unsaturated aldehydes. These sequence-specific carbinolamine cross-links are anticipated to interfere with DNA replication and contribute to acrolein-mediated genotoxicity.
authors.affiliation: Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, USA.
authors.forename: Young-Jin
authors.initials: YJ
authors.lastname: Cho
authors.forename: Hye-Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Hai
authors.initials: H
authors.lastname: Huang
authors.forename: Alvira
authors.initials: A
authors.lastname: Slutsky
authors.forename: Irina G
authors.initials: IG
authors.lastname: Minko
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Lubomir V
authors.initials: LV
authors.lastname: Nechev
authors.forename: Ivan D
authors.initials: ID
authors.lastname: Kozekov
authors.forename: Albena
authors.initials: A
authors.lastname: Kozekova
authors.forename: Pamela
authors.initials: P
authors.lastname: Tamura
authors.forename: Jaison
authors.initials: J
authors.lastname: Jacob
authors.forename: Markus
authors.initials: M
authors.lastname: Voehler
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Harris
authors.forename: R Stephen
authors.initials: RS
authors.lastname: Lloyd
authors.forename: Carmelo J
authors.initials: CJ
authors.lastname: Rizzo
authors.forename: Michael P
authors.initials: MP
authors.lastname: Stone
mesh_terms: D000171:Acrolein / Q000031:analogs & derivatives / Q000737:chemistry*; D002247:Carbon Isotopes; D018899:CpG Islands; D003432:Cross-Linking Reagents / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D018736:DNA Adducts / Q000737:chemistry*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000737:chemistry; D006860:Hydrogen Bonding; D007553:Isotope Labeling; D008958:Models, Molecular; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D009842:Oligopeptides / Q000737:chemistry; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D002247:Carbon Isotopes; D003432:Cross-Linking Reagents; D018736:DNA Adducts; D009587:Nitrogen Isotopes; C424742:OH-1,-N(2)-propano-2'-deoxyguanosine; D009841:Oligonucleotides; D009842:Oligopeptides; D000171:Acrolein; D004247:DNA; D003849:Deoxyguanosine