DNA interchain cross-links formed by acrolein and crotonaldehyde.
Acrolein and higher alpha,beta-unsaturated aldehydes are bifunctional genotoxins. The deoxyguanosine adduct of acrolein, 3-(2-deoxy-beta-d-erythro-pentofuranosyl)-5,6,7,8-tetrahydro-8-hydroxypyrimido[1,2-a]purin-10(3H)-one (8-hydroxy-1,N(2)-propanodeoxyguanosine, 2a), is a major DNA adduct formed by acrolein. The potential for oligodeoxynucleotide duplexes containing 2a to form interchain cross-links was evaluated by HPLC, CZE, MALDI-TOF, and melting phenomena. Interchain cross-links represent one of the most serious types of damage in DNA since they are absolute blocks to replication. In oligodeoxynucleotides containing the sequence 5'-dC-2a, cross-linking occurred in a slow, reversible manner to the extent of approximately 50%. Enzymatic digestion to form 3-(2-deoxy-beta-d-erythro-pentofuranosyl)-5,6,7,8-tetrahydro-8-(N(2)-2'-deoxyguanosinyl)pyrimido[1,2-a]purin-10(3H)one (5a) and reduction with NaCNBH(3) followed by enzymatic digestion to give 1,3-bis(2'-deoxyguanosin-N(2)-yl)propane (6a) established that cross-linking had occurred with the exocyclic amino group of deoxyguanosine. It is concluded that the cross-link is a mixture of imine and carbinolamine structures. With oligodeoxynucleotide duplexes containing the sequence 5'-2a-dC, cross-links were not detected by the techniques enumerated above. In addition, (15)N-(1)H HSQC and HSQC-filtered NOESY spectra carried out with a duplex having (15)N-labeling of the target amino group established unambiguously that a carbinolamine cross-link was not formed. The potential for interchain cross-link formation by the analogous crotonaldehyde adduct (2b) was evaluated in a 5'-dC-2b sequence. Cross-link formation was strongly dependent on the configuration of the methyl group at C6 of 2b. The 6R diastereomer of 2b formed a cross-link to the extent of 38%, whereas the 6S diastereomer cross-linked only 5%.
Kozekov
Ivan D
ID
Department of Chemistry and Center in Molecular Toxicology, Vanderbilt University, Nashville, TN 37235, USA.
Nechev
Lubomir V
LV
Moseley
M Scott
MS
Harris
Constance M
CM
Rizzo
Carmelo J
CJ
Stone
Michael P
MP
Harris
Thomas M
TM
D000171:Acrolein / Q000737:chemistry*; D000447:Aldehydes / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D018899:CpG Islands; D003432:Cross-Linking Reagents / Q000737:chemistry*; D004247:DNA / Q000737:chemistry; D018736:DNA Adducts / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism; D013379:Substrate Specificity
D000447:Aldehydes; D003432:Cross-Linking Reagents; D018736:DNA Adducts; D000171:Acrolein; D004247:DNA; C012796:2-butenal