It has been shown previously that two structure domains of bleomycin m
ediate the interaction of the antitumor antibiotic with DNA. At least
three lines of evidence indicate that the metal binding domain is the
predominant partner, and is responsible for the sequence selectivity o
f DNA cleavage observed for Fe(II).BLM. The bithiazole + C-terminus ha
s been shown previously to bind to DNA, but not to exhibit any sequenc
e selectivity. presently, it is shown that the bithiazole + C-terminus
may also exhibit sequence selectivity, albeit not in the same fashion
as bleomycin itself. The potential of this selectivity to contribute
to the recognition of high affinity sites on DNA by bleomycin is discu
ssed.