MOLECULAR RECOGNITION OF GUANOSINE AND 2-ACETYLAMINOFLUORENE-MODIFIEDGUANOSINE - A COMPARATIVE-STUDY

The ability of an abiotic receptor, 7-acetylamino-2-methyl-1,8-naphthy ridine, to bind to guanosine was analysed by a combination of NMR dete rminations and molecular modeling studies. The results indicate that t his receptor simulates the base-pairing properties of cytidine in its Watson-Crick interaction with guanosine, Binding of the same receptor to N-(guanosin-8-yl)-2-acetylaminofluorene, the guanosine adduct conta ining the carcinogen 2-acetylaminofluorene, was found to occur in a si milar manner. The calculated binding energies show that the molecular recognition of the adduct is lower than that of the unmodified guanosi ne. The theoretical studies suggest that the predominance of an abnorm al low energy syn conformation for the adduct is the main structural f eature accounting for the observed decrease of the host-guest interact ion.