Fig. 3.

Autoradiograms of gel shift assay and binding affinity of E. coli MutS protein bound with each of six different oligoduplexes, which contained either O⁶-MeG:T, O⁶-MeG:C, O⁶-EtG:T, O⁶-EtG:C, G:T or G:C base pair. Each 5′-³²P-labeled duplex was incubated with purified MutS and subjected to native polyacrylamide gel electrophoresis. The percent of duplexes binding to MutS was calculated by dividing the densities of bands showing complexes by total densities of all labeled-bands at each concentration of MutS. The concentrations of MutS used were (left to right) 0, 10, 25, 50, 75 100, 150, 250, 300 and 500 nM.