FIG. 2.

Binding of hMutSα and hMutSβ to DNA containing B[a]PDE. Unless otherwise indicated, gel shift assays were performed in 25-μl reaction mixtures containing 0.5 pmol of ³²P-labeled oligonucleotide duplexes, 0.25 pmol of purified hMutSα or hMutSβ, 0.4 mg of double-stranded-f1MR3 DNA (competitor DNA), 10 mM HEPES-KOH (pH 7.5), 110 mM KCl, 1 mM EDTA, 1 mM dithiothreitol, and 4% glycerol. After 20 min of incubation on ice, 5 μl of 50% sucrose was added. The samples were fractionated at room temperature through a 6% nondenaturing polyacrylamide gel in 6.7 mM Tris-acetate (pH 7.5)–1 mM EDTA with buffer recirculation. NT, nucleotide.