FIG. 1.

EMSA with H₆-CodY. DNA binding of CodY to the gdhA promoter region (140 bp) and the psaR promoter region (147 bp) in the absence or presence of BCAA (5 or 10 mM ILV) and/or GTP (5 mM). In each series, successive lanes contained increasing amounts of CodY (0, 100, 250, 500, 1,000, and 2,000 nM). In the sequences (top), bold letters indicate the CodY recognition site (or its position in the mutated sequence) and the start of the coding sequence is in bold and italic letters. Histograms (bottom) show the percentages of free probe (DNA fragment) left. The wild-type gdhA promoter region (A); the mutated gdhA promoter with the CodY box replaced with random nucleotides (B); the wild-type psaR promoter, not regulated by CodY (C); and the mutated psaR promoter with a CodY box introduced 100 bp upstream of the coding sequence (D) are shown.