X-Ray diffraction analyses of the natural isoquinoline alkaloids Berberine and Sanguinarine complexed with double helix DNA d(CGTACG)

The first crystal structures of Berberine and Sanguinarine intercalated with a d(CGTACG)(2) DNA sequence were obtained by X-ray diffraction analysis at 2.3 angstrom resolution. Both drugs join the end of two two-molecules DNA units, stacked in a non-classic intercalation site formed by six bases. Sanguinarine interacts with d(CGTACG)(2) DNA in its iminium form.