Assignment of DNA binding sites for DAPI and bisbenzimide (Hoeschst 33258). Comparative footprinting study

ArticleinBiochimica et Biophysica Acta 949(2):158-68 · March 1988with37 Reads
Impact Factor: 4.66 · DOI: 10.1016/0167-4781(88)90079-6 · Source: PubMed


    DNA binding sites for the minor groove-binding ligands DAPI (4',6-diamidine-2-phenylindole) and Hoechst 33258 (bisbenzimide) have been analysed using DNAase I and micrococcal nuclease footprinting techniques. Both drugs appear to bind to AT-rich regions containing at least four such basepairs. Hoechst 33258 seems to bind relatively poorly to nucleotide sequences containing the alternating step TpA. However, in contrast to DAPI, it can more readily accommodate the presence of guanosine residues at the end of the binding site. We compare the DNA binding sites for DAPI and Hoechst 33258 with those determined for the related minor groove-binding ligands, berenil, netropsin and distamycin A, under comparable conditions, and discuss the importance of using different footprinting probes when analysing drug-DNA interactions.