FIG. 3.

Activities of mutant P_L promoters determined by P_L::lacZ fusions (pBKM1 through pBKM14) in transformants of E. coli JW1 grown in Luria-Bertani medium. The strains harboring pBK and pBK2241 served as background and wild-type references, respectively. The specific activity (sp act) values represent mean values obtained from at least three independent determinations. They varied up to ±5 mU/mg in the low-level activity range (2 to 60 mU/mg) and up to ±30 mU/mg in the high range (510 to 930 mU/mg).