Enantiospecific recognition of DNA by bleomycin

The specific double-stranded DNA recognition mechanism of bleomycin was investigated using L-d(CGCGCG), the enantiomer of natural D-d(CGCGCG). The L-enantiomer was clearly shown not to be cleaved at all by bleomycin under the same conditions that the corresponding D-enantiomer was cleaved, but the conventional DNA-binding domain of bleomycin was able to bind to the L-enantiomer to essentially the same extent as the natural one, as shown by 1 H NMR titration experiments. However, other protons in the metal-binding domain and linker moiety showed different behaviors depending on the chirality of DNA