Promoter sequence analysis in Bacillus and Escherichia: construction of strong promoters in E. coli

Many derivatives of the nprM promoter of Bacillus stearothermophilus and the strong early promoter, A3, of coliphage T3 were designed and chemically synthesized. These promoters consisted of some or all of the AT box, consensus sequence, tac promoter sequence, spacer, and lac operator. The promoter activities were assessed by their ability to express the cat gene in Escherichia coli. One of the derivatives of the A3 promoter, which contained the lac operator, was much stronger (about 3.5 times) than the tac promoter. The promoter activities in E. coli were considerably modified by the substitutions in the -43 (AT box) and -35 regions.