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
Mentions: The NMR data provided evidence that the anomeric carbon of the 2-deoxyribose adduct was attached at the exocyclic N6-amino group of the 2′-deoxyadenosine unit, as shown in structure 6. For example, an 15N-HMBC experiment revealed three-bond coupling between the N6-nitrogen and the H2″ protons of the 2-deoxyribose adduct (Figure 3). Furthermore, the TOCSY spectra showed that the N6-H, the H1″ and H2″ protons reside in the same spin system (Figure 4). Overall, the NMR analysis established that the reaction of dA with 2-deoxyribose provided the desired cross-link remnant 6.
Affiliation: Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, MO 65211, USA.