Biomimetic preparation and structure determination of QGI, one of the quinoline-DNA base adducts formed in cells treated with 4-nitroquinoline 1-oxide.

One of the quinoline-DNA base adducts, QGI, formed in cells treated with 4-nitroquinoline 1-oxide, was readily prepared in vitro from GMP or dGMP and 4-hydroxy-aminoquinoline 1-oxide in the presence of ATP, L-serine, and seryl tRNA synthetase. Synthetic seryl-AMP could be substituted for the enzymatic activation system for QGI formation. Chemical and spectral analyses of the adduct thus prepared revealed that QGI can be formulated as N4-(guan-8-yl)-4-aminoquinoline 1-oxide, the structure of which is identical with the modified base structure involved in the deoxyguanosine-quinoline adduct, dGIII (nomenclature of Loucheux-Lefebvre et al.) obtained by the chemical modification of deoxyguanosine with monoacetyl and diacetyl derivatives of 4HAQO.