FIG. 4.

C12O (A and C) and β-Gal (B) activities measured in E. coli HB101 and different P. putida strains carrying different tnpA promoter constructs. P. putida PaW85 carries in the chromosome a copy of Tn4652, and strain PRS2000 is Tn4652 free. P. putida A8759 is an ihfA-deficient derivative of strain KT2442. Bacterial strains and tnpA gene promoter constructs are listed in Table 1. Data (means ± standard deviations) of at least five independent experiments are presented. For plasmid pEST1332, the basal level of expression of C12O is less than 0.01 μmol/min/mg; for pKTlacZ, the level of expression of β-Gal is less than 2 nmol/min/mg.