Chemical and structural characterization of interstrand cross-links formed between abasic sites and adenine residues in duplex DNA.
Bottom Line: A synthetic standard was prepared for the putative nucleoside cross-link remnant 6 in which the anomeric carbon of the 2-deoxyribose residue was connected to the exocyclic N(6)-amino group of dA.These findings establish the chemical structure of the dA-Ap cross-link released from duplex DNA and may provide methods for the detection of this lesion in cellular DNA.Both the nucleoside cross-link remnant 6: and the cross-link in duplex DNA were quite stable at pH 7 and 37°C, suggesting that the dA-Ap cross-link could be a persistent lesion with the potential to block the action of various DNA processing enzymes.
Affiliation: Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, MO 65211, USA.Show MeSH
Related in: MedlinePlus
Mentions: Before endeavoring to use the synthetic cross-link remnant 6 as an analytical standard, we examined the chemical stability of this material. Compound 6 can be classified broadly as an N-aryl glycosylamine. Compounds of this type have the potential to undergo hydrolytic decomposition to release the free sugar and the unmodified arylamine (38–40). We used HPLC to examine the stability of 6 in sodium phosphate buffer (50 mM, pH 7) at both 37 and 75°C. First, we noted that all four isomers of 6 described above in the context of the NMR experiments could be resolved by reversed-phase HPLC (Figure 5). Second, we found that the synthetic cross-link remnant 6 was remarkably stable, decomposing to release unmodified dA with a half-life of 65 days at 37°C and 3 days at 75°C (Figure 6).
Affiliation: Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, MO 65211, USA.