DNase 1 footprinting analysis of SabR binding to the upstream of sanG. A, DNase 1 footprinting experiments. The amounts of SabR-His6 used in lane 1 to 7 were 0, 208, 260, 390, 520, 650 and 780 nM, respectively. The region protected against DNase 1 digestion by SabR was indicated by solid line. B, Nucleotide sequence of sanG promoter and SabR-binding sites. The transcription start point (TSP) of sanG is indicated by an arrow. The nucleotide sequence of SARE protected against DNase 1 digestion by SabR is underlined. C, Comparison of SARE with the ARE consensus sequence recognized by the Streptomyces γ-butyrolactone receptors. Identical residues are highlighted in black. Arrows indicate the position of the 22 bp inverted repeat sequence identified as a consensus sequence (ARE box) recognized by the γ-butyrolactone autoregulator receptor protein ArpA[39].