Gel shift assay. Fluorescently labeled DNA probes were incubated with purified PdhR protein. All samples were directly loaded onto a polyacrylamide gel after incubation. Arrows indicate the free, filled arrows the shifted DNA, respectively. A The PdhR binding site of the pdhR-aceEF-ldpA operon was incubated with increasing amounts of PdhR as indicated (9, 18, 28, 37 pmol). B The PdhR binding site was incubated with 39 pmol PdhR (lane 2) and with PdhR and 50 mM pyruvate (lane 3). C The Mlc consensus sequence was incubated with purified PdhR (18, 28, 37, 46 pmol). D The operator promoter sequence of lipA (ca 500 bp in front of the start codon) was incubated with PdhR (33, 44, 50, 55 pmol) E The lipA operator promoter was incubated with 44 pmol PdhR (lane 2) and with PdhR and 100 mM pyruvate (lane 3).