FIG. 4.

Identification of the fxbA promoter. (A) The 5′ terminus of the fxbA transcript was determined by primer extension using oligonucleotide fxbA23 and RNA prepared from cultures of strains mc²155 and SM3 growing in 7H9L or 7H9H. Lanes: 1, mc²155 in 7H9L; 2, mc²155 in 7H9H; 3, SM3 in 7H9L; 4, SM3 in 7H9H. The nucleotide sequencing ladder shown at the left was obtained with oligonucleotide fxbA23 as the primer and plasmid pKSfxbA as the template. (B). The putative −10 and −35 boxes of the fxbA promoter are underlined, as are a possible RBS and the start codon. The TSP is indicated with an arrow. The consensus sequence for E. coli ς⁷⁰ promoters is shown for comparison. Uppercase denotes more than 50% conservation.