FIG. 1.

Promoter architecture and design of spacing mutations. The numbers indicate distances from the transcription start site (indicated by a bent arrow). The numbers for the acfA promoter are underlined to distinguish them from the numbers for the acfD promoter. The boxes indicate the positions of −35 and −10 promoter elements. The arrows below the thick black lines indicate the positions of toxboxes at each promoter. The open triangles indicate the locations of insertion or deletion mutations. “+/−p” indicates that insertions or deletions were made between the promoter-proximal toxbox and the −35 box, and “+/−t” indicates that insertions or deletions were made upstream of the toxbox (for aldA) or between the toxboxes.