Figure 3. Expression of mxaF-xylE and xoxF1-xylE promoter fusions in M. extorquens strain AM1.

The mxaF and xoxF1 promoter activities were determined by measuring catechol 2,3-dioxygenase activity (XylE) in crude cell extracts of strains grown in methanol (black bar) or succinate (white bar) media containing 30 µM La³⁺ and/or Ca²⁺. Results are shown as means with standard deviations (n = 3).