Different bindings of the minor groove ligands DAPI and Hoechst 33258 to multimers of the curved (CA4T4G) and noncurved (CT4A4G) DNA sequences.

Equilibrium binding properties of DAPI and Hoechst for prototype curved (CA4T4G)n and straight (CT4A4G)n DNAs were derived from fluorescence intensity. Both decamers display a single strong binding site for each ligand. Hoechst binds seven times stronger to curved than to straight DNA. An additional cooperative, much weaker binding site is found for DAPI.