Figure 3.

(a) Phosphoimagery of 20% polyacrylamide gels shows mismatch-specific cleavage by the rhodium(III) complex after DNA photocleavage by 1 μM [Rh(bpy)₂chrysi]Cl₃ (BC) and 0.1–100 μM [Rh(bpy)₂phzi]Cl₃ (BZ) on 5′-³²P-labeled (indicated by *) CC mismatch-containing 31/41-mer DNA duplex (1 μM). (b) All samples were prepared in 10 mM Tris, pH 8.0/50 mM NaCl. All irradiations were at 313 nm for 15 min after DNA photocleavage by varying the concentration of [Rh(bpy)₂chrysi]Cl₃ (BC) and [Rh(bpy)₂phzi]Cl₃ (BZ), as well as at different wavelengths for [Rh(bpy)₂phzi]Cl₃. It is notable that BC does not cleave the DNA at concentrations up to 100 nM, whereas BZ already shows a cleavage at 10 nM at the mismatch site. AG and CT, Maxam-Gilbert sequencing reactions; DC, dark control DNA sample without irradiation; LC, the light control sample irradiated in the absence of metal complex.