Synthesis and Characterization of DNA Containing O6-Carboxymethylguanine

O6-Carboxymethylguanine was formed in DNA treated with N-nitrosoglycocholic acid and believed to be implicated in human gastrointestinal and colorectal tumour. An efficient method is presented here for synthesis of oligodeoxynucleotides containing O6-carboxymethylguanine at pre-determined positions. The synthetic protocol also allows for production of oligomers containing O6-aminocarbonylmethylguanine. These guanine-modified oligomers have been fully characterized and could provide a useful tool for biological studies of these modified bases.