STUDIES ON THE ABILITY OF MINOR-GROOVE BINDERS TO INDUCE SUPERCOILINGIN DNA

The effect of various non-intercalating minor groove binders on closed circular DNA in the presence of topoisomerase I has been studied by m eans of agarose gel electrophoresis. Analogues of the netropsin series (lexitropsins) and SN-6999 can effectively produce positive supercoil s, as indicated by analysis of the topoisomers in the presence of chlo roquine and the evaluated linking number changes. Analogues of the dis tamycin series are less effective, and bisquaternary ammonium heterocy cles, as well as DAPI and pentamidine, were found to be ineffective li gands. The large differences observed in the ability of minor groove b inders to induce positive supercoils are discussed.