Identification and characterization of a reaction product of 2 '-deoxyoxanosine with glycine

2'-Deoxyoxanosine (dOxo) is a novel DNA lesion produced from dGuo by reacti on with nitrous acid or nitric oxide [Suzuki, T., Yamaoka, R., Nishi, M., I de, H., and Makino, K. (1996) J. Am. Chem. Sec. 118, 2515-2516]. We investi gated the reaction of dOxo with glycine (Gly) under physiological condition s. When 5 mM dOxo was incubated with 500 mM Gly in 100 mM sodium phosphate buffer (pH 7.4) at 37 degrees C, an unknown product was formed exclusively. The yield of the product was 86% at an incubation time of 3 h, Using spect rometric data, it was identified as a ring-opened adduct containing an amid e bond between the carbonyl group of dOxo and the amino group of Gly. The a dduct was very stable (t(1/2) = 1280 h) under physiological conditions. Fur thermore, dOxo in oligodeoxynucleotide reacted with Gly, yielding the same adduct. These results suggest that dOxo formed in DNA may react with Gly pr esent in cells, resulting in adduct formation in vivo.