Frameshift mutagenesis of 9-aminoacridine derivatives in Salmonella typhimurium

It has been noted that 9-aminoacridine reverts a his C frameshift but not one in his D in the Salmonella strains used in the Ames test, without metabolic activation. The 2 sites differ in the arrangement of G and C residues present. We show here that a series of 9-aminoacridine derivatives exhibits the same selectivity as 9-aminoacridine provided there is at least one exocyclic amino hydrogen at the central ring position in acridines, or the analogous site in aminoquinolines. The results are consistent with a model derived from NMR experiments on 9-aminoacridine binding to dinucleoside phosphates, in which the N-H group is situated in the duplex so as to participate in a hydrogen bond with one base while excluding its complementary partner, thereby provoking mismatching. We also report a strong difference in the dose-response behavior of 9-aminoacridine, quinacrine and a bifunctional derivative of quinacrine.