DNA binding of RhPt. Left: Competition titration of increasing
concentrations of RhPt (0–50 μM) with 1 μM rac-[Rh(bpy)2chrysi]3+ on 1 μM
5′-[32P] labeled 17mer duplex DNA with a CC mismatch.
Controls without irradiation (Øhν), and
without Rh (ØRh) were included. RhPt inhibits photocleavage by
[Rh(bpy)2chrysi]3+ at the mismatched site. Right:
DMS footprinting of duplex DNA containing a CC mismatch. Lanes (left
to right): Maxam–Gilbert sequencing (C+T; A+G); 3, DMS alone; 4, oxaliplatin (1 μM); 5, RhPt (1 μM); 6, RhPt (50 μM). Bands of
high electrophoretic mobility indicate cleavage at guanine residues;
covalent binding of platinum to guanine inhibits cleavage.