Ll. Guan et al., GUANINE-SPECIFIC BINDING BY BLEOMYCIN NICKEL(III) COMPLEX AND ITS REACTIVITY FOR GUANINE-QUARTET TELOMERIC DNA, Biochemistry, 32(24), 1993, pp. 6141-6145
Bleomycin-Ni(III) [BLM-Ni(III)] complex, generated from oxidation of t
he corresponding BLM-Ni(II) complex with Ir(IV) or oxone, binds to sin
gle-stranded DNA and causes strand scission at specific guanine sites.
In the telomeric-like oligodeoxynucleotide d(T2G4)4, the cleavage by
the BLM-Ni(III) complex occurs preferentially at positions G-9 and G-1
5 in loop regions. By contrast, this Ni(III) complex does not induce c
leavage of G-quartet d(G4T4G4)2, which contains no loop guanines, ESR
evidence supports that binding of the N-7 position of guanine occurs a
xially to the Ni(III) center in BLM. The present results provide inter
esting insights into Ni-BLM chemistry.