Site-specific Synthesis and Characterization of Oligonucleotides Containing an N6-(2-Deoxy-d-erythro-pentofuranosyl)-26-diamino-34-dihydro-4-oxo-5-N-methylformamidopyrimidine Lesion the Ring-Opened Product from N7-Methylation of Deoxyguanosine

摘要

A phosphoramidite reagent of N⁶-(2-deoxy-d-erythro-pentofuranosyl)-2,6-diamino-1,4-dihydro-4-oxo-5-N-methylformamidopyrimidine (MeFapy-dGuo) lesions was synthesized in four steps from 2′-deoxyguanosine. Fapy nucleosides can rearrange to the pyranose form when the 5′-hydroxyl group is unprotected. The phosphoramidite was incorporated into oligonucleotides using solid-phase synthesis by adjusting the deprotection time for removal of the 5′-dimethoxytrityl group of the MeFapy-dGuo nucleotide, thereby minimizing its rearrangement to the ribopyranose. The furanose and pyranose forms were differentiated by a series of 2D NMR experiments.