FIG. 3.

ssDNA binding activity of PC4 is required for mutation suppression in E. coli fpg mutY. Histidine-tagged forms of PC4 and its ssDNA binding-defective mutants W89A and β2β3 are expressed from the l-arabinose-inducible araBAD promoter present on the pBAD24 vector. (A) Upper panels show the mutator activity in the absence of l-arabinose, lower panels show the mutator activity of wild-type and mutant forms of PC4 after induction by l-arabinose. (B) Left section shows the Western blotting using antihistidine antibody to determine levels of wild-type (WT) and mutant protein expression; the right section shows the same gel stained with Coomassie brilliant blue.