FIG. 3.
Mutation in IF1 affects its nucleic acid melting activity. (A) Schematic drawing of the DNA substrate. The numbering of thymines corresponds to that in panel B. (B) The melting of the stem structure of the DNA substrate (with a 4-nt 5′ overhang and a 9-bp stem) with addition of CspE or IF1 was followed with KMnO4 probing as described in Materials and Methods. Results of a control reaction without added protein (lane 1) and of reactions with added CspE (lane 2), wild-type IF1 (lane 3), or IF1(H34R) (lane 4) are shown. Thymines in the stem are numbered 1 to 5. A thymine residue that lies immediately outside the stem region is numbered 6. The gel is representative of an experiment carried out at least three times.