DNA bending induced by covalently bound drugs. Gel electrophoresis and chemical probe studies.

Modification of nucleotide residues arising from the covalent binding of a drug or as a result of irradiation with ultraviolet light can induce distortion of the DNA double helix. The purpose of this review is to show that, from investigation of the electrophoretic mobility of the modified DNA fragments, one can deduce whether the distortions behave more as the centers of directed bends or as hinge joints. It is also demonstrated that chemical probes are a complementary tool for the analysis of distortions at the nucleotide level.