Interaction of bleomycin with DNA.

Abstract

The sequence of oligonucleotides produced by the action of bleomycin [an antineoplastic drug] and Fe2+ on double- and single-stranded [bacteriophage .vphi.x174] DNA was determined. In the presence of Fe2+ bleomycin promotes cleavage at G-T and G-C sequences, while high concentrations of Fe2+ alone result in strand scission that is not base specific. In the presence of bleomycin and Fe2+, pyrimidine bases located to the 3'' side of guanosine are released preferentially and a low MW product that forms a chromophore with thiobarbituric acid is produced from the deoxyribose moiety. Oligonucleotides produced by the action of bleomycin differ slightly in electrophoretic mobility from those produced by chemical or enzymatic cleavage. A model is proposed to explain the interactions of bleomycin with DNA.