OXIDATIVE THYMINE DIMER REPAIR IN THE DNA HELIX

The metallointercalator Rh(phi)(2)DMB(3+) (phi, 9,10-phenanthrenequino ne diimine; DMB, 4,4'-dimethyl-2,2'-bipyridine) catalyzed the repair o f a thymine dimer incorporated site-specifically in a 16-base pair DNA duplex by means of visible light, This repair could be accomplished w ith rhodium noncovalently bound to the duplex and at long range (16 to 26 angstroms), with the rhodium intercalator tethered to either end o f the duplex assembly, This long-range repair was mediated by the DNA helix, Repair efficiency did not decrease with increasing distance bet ween intercalated rhodium and the thymine dimer, but it diminished wit h disruption of the intervening pi-stack.