FIG 3.

SDS-PAGE analysis of the purified BmrRHis and specific binding of BmrRHis to its own promoter. (A) Lane M, dual-color-prestained broad-molecular-size protein markers (10 to 180 kDa); lane 1, L. lactis NZCK1 with 10 ng·ml⁻¹ nisin induction; lane 2, L. lactis BmrRHis with 10 ng·ml⁻¹ nisin induction; lane 3, protein sample from NZCK1 after purification; lane 4, purified recombinant BmrRHis from L. lactis BmrRHis. (B) DNA probes containing an intact palindromic sequence in the BmrR binding site or a mutated sequence. (C) Lane 1, 20 fmol labeled probes alone; lane 2 to lane 4, 20 fmol probes and 10, 20, and 30 ng·μl⁻¹ BmrRHis, respectively. (D) Lane 1, 20 fmol labeled probes alone; lane 2 to lane 4, 10 ng·μl⁻¹ BmrRHis with 20 fmol probes, 20 fmol probe up⁻, and 20 fmol probe down⁻, respectively.