FIG. 1.

Constructs used in this study. The sequences shown were cloned into the pKK232-8 plasmid vector for E. coli at BamHI and HindIII restriction sites. The p_R promoter was inactivated by introduction of three base pair substitutions in its −10 region, which are shown in boldface type. The −10 and −35 regions are boxed. The position of the region shortened in the deletion mutants is indicated in italic letters. The deletions start from the upstream edge of the −35 of the p_RM promoter and progress towards the p_R promoter. Constructs are designated as Dn, with n indicating the number of base pairs deleted. For example, the sequence between the −35 regions is CACGCACGG (top strand in the figure) for the D3 mutant.