title: 1,N2-deoxyguanosine adducts of acrolein, crotonaldehyde, and trans-4-hydroxynonenal cross-link to peptides via Schiff base linkage.
abstract: DNA-protein cross-links (DPCs) are formed upon exposure to a variety of chemical and physical agents and pose a threat to genomic integrity. In particular, acrolein and related aldehydes produce DPCs, although the chemical linkages for such cross-links have not been identified. Here, we report that oligodeoxynucleotides containing 1,N(2)-deoxyguanosine adducts of acrolein, crotonaldehyde, and trans-4-hydroxynonenal can form cross-links with the tetrapeptide Lys-Trp-Lys-Lys. We concluded that complex formation is mediated by a Schiff base linkage because DNA-peptide complexes were covalently trapped following reduction with sodium cyanoborohydride, and pre-reduction of adducted DNAs inhibited complex formation. A previous NMR study demonstrated that duplex DNA catalyzes ring opening for the acrolein-derived gamma-hydroxy-1,N(2)-propanodeoxyguanosine adduct to yield an aldehydic function (de los Santos, C., Zaliznyak, T., and Johnson, F. (2001) J. Biol. Chem. 276, 9077-9082). Consistent with this earlier observation, the adducts under investigation were more reactive in duplex DNA than in single-stranded DNA, and we concluded that the ring-open aldehydic moiety is the induced tautomer in duplex DNA for adducts exhibiting high relative reactivity. Adducted DNA cross-linked to Arg-Trp-Arg-Arg and Lys-Trp-Lys-Lys with comparable efficiency, and N(alpha)-acetylation of peptides dramatically inhibited trapping; thus, the reactive nucleophile is located at the N-terminal alpha-amine of the peptide. These data suggest that Schiff base chemistry can mediate DPC formation in vivo following the formation of stable aldehyde-derived DNA adducts.
authors.affiliation: Sealy Center for Molecular Science and the Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston, Texas 77555-1071, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Kurtz
authors.forename: R Stephen
authors.initials: RS
authors.lastname: Lloyd
mesh_terms: D000171:Acrolein / Q000737:chemistry*; D000447:Aldehydes / Q000737:chemistry*; D000595:Amino Acid Sequence; D003432:Cross-Linking Reagents; D018736:DNA Adducts / Q000737:chemistry*; D003849:Deoxyguanosine / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D009842:Oligopeptides / Q000737:chemistry*; D012545:Schiff Bases
chemical_list: D000447:Aldehydes; D003432:Cross-Linking Reagents; D018736:DNA Adducts; D009842:Oligopeptides; D012545:Schiff Bases; D000171:Acrolein; C012796:2-butenal; D003849:Deoxyguanosine; C027576:4-hydroxy-2-nonenal