CONFORMATIONAL-CHANGES INDUCED IN DNA BY INVITRO REACTION WITH N-HYDROXY-N-2-AMINOFLUORENE

The conformation of DNA modified in vitro by ths covalent binding of N-OH-AF was investigated by ultraviolet absorbance, circular dichroism and by radioimmunoassay using specific antibodies against Guo-AAF and nDNA-AAF. The results obtained by both physico-chsmical and immunological methods are in agreement with a model involving destabilized regions in the double helical DNA around the carcinogen molecule in which, however, the -AF residues are stacked to the adjacent nucleotides. The RIA results show that the -AF residues are less accessible to antibodies in native than in denatured DNA-AF and thus suggest -AF residues partially buried in the interior of the DNA helix. The present model is compared to the one existing for DNA modified by reaction with N-AcO-AAF (DNA-AAF) (1,2). © 1979 Information Retrieval Limited.