Book of Abstracts: Albany 2011
June 14-18 2011
©Adenine Press (2010)
Post-synthetic Generation of Fapy-dG Lesion within Oligodeoxynucleotides: Differential Anomeric Impacts on DNA Duplex Properties
Cellular DNA is a target for oxidative stress arising from exposure to environmental and endogenous sources that account for thousands of oxidatively damaged bases per day. The prominent oxidative lesion, imidazole ring opened N6-(2-Deoxy-a,b-D-erythro-pentafuranosyl)-2,6-diamino-4-hydroxy-5-formylamidopyrimidine (Fapy-dG) is one of the most common lesions of this type (1). Its formation has been reported under various experimental conditions, and its accumulation is associated with progression of many age-related diseases and cancer (2, 3). Structural and thermodynamic studies of this lesion require development of universal and reliable synthetic strategy to incorporate cognate Fapy-dG site-specifically within any oligodeoxynucleotide sequence. We elaborated the scheme that consists of a two-step post-synthetic treatment of the modified nitropyrimidine oligonucleotide and does not require purification of the intermediate product (4). This approach has been successfully applied to the preparation of isotopically labeled Fapy-dG in DNA for subsequent solution state NMR studies. We demonstrated that the lesion exists in DNA in a several slowly interconverting anomeric and rotameric forms (4). The anomeric forms of the Fapy-dG containing synthetic oligonucleotides have been successfully separated using ion-exchange HPLC. The resultant anomeric duplexes exhibit distinct thermal and thermodynamic profiles that are characteristic of α- and β-anomers.
1Department of Pharmacological Sciences