title: Chemistry of the alkali-labile lesion formed from iron(II) bleomycin and d(CGCTTTAAAGCG).
abstract: Two sets of products are formed from DNA upon treatment with Fe(II).bleomycin + O2. One set, which is believed to derive from a C-4' hydroperoxy derivative of the DNA deoxyribose moiety, includes the four possible base propenals, as well as DNA oligomers having deoxynucleoside 3'-(phosphoro-2"-O-glycolates) at their 3'-termini. The other set of products consists of free bases and alkali-labile lesions, the latter of which had not previously been characterized structurally. By use of the self-complementary dodecanucleotide d(CGCTTTAAAGCG) having a site modified by Fe-bleomycin three nucleotides from the 5'-end, it has been possible to characterize the alkali-labile product as a C-4' hydroxyapurinic acid. When the bleomycin-treated dodecanucleotide was treated with agents that effected decomposition of the alkali-labile lesion, products of the form CpGpx were obtained, and these proved useful for structural characterization of the alkali-labile lesion. Treatment with alkali produced CpGpx, where x was 2,4-dihydroxycyclopentenone. Alternatively, treatment with hydrazine provided a pyridazine derivative, and aqueous alkylamines led to formation of CpGp itself. The structures of all dinucleotides produced from the alkali-labile lesion were verified by direct comparison with authentic synthetic samples.
mesh_terms: D001483:Base Sequence; D001761:Bleomycin / Q000031:analogs & derivatives; D004247:DNA; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis
chemical_list: D007202:Indicators and Reagents; D009838:Oligodeoxyribonucleotides; C023503:iron bleomycin; D001761:Bleomycin; D004247:DNA