Change of the Higher Order Structure in a Giant DNA Induced by 4′, 6-Diamidino-2-phenylindole as a Minor Groove Binder and Ethidium Bromide as an Intercalator

From a quantitative study of the contour length and the persistent length of DNA molecules with fluorescence microscopy, it is shown that 4′, 6-diamidino-2-phenylindole (DAPI) and ethidium bromide (EB) change the higher order structure of DNA in a different manner.