DNA-binding affinities and sequence selectivity of quaternary benzophenanthridine alkaloids sanguinarine, chelerythrine, and nitidine Original Research Article

A comparative study on the intercalating binding of sanguinarine, chelerythrine, and nitidine with CT DNA, poly(dG–dC)·poly(dG–dC), poly(dA–dT)·poly(dA–dT), and seven sequence-designed double-stranded oligodeoxynucleotides has been performed using fluorometric and spectrophotometric techniques, aiming at providing insights into their sequence selectivity for DNA-binding. The results show that both sanguinarine and nitidine bind preferentially to DNA containing alternating GC base pairs [d(TGCGCA)2], while chelerythrine exhibits quite distinct sequence selectivity from sanguinarine, which shows a high specificity for DNA containing contiguous GC base pairs [5′-TGGGGA-3′/3′-ACCCCT-5′].