Figure 1. CorE is involved in copper homeostasis.

(A) Copper up-regulation of corE. β-gal specific activity was determined in cell extracts of the WT (blue lines) and ΔcorE (red lines) strains (harboring the fusion corE-lacZ) from CTT agar plates containing no copper (open symbols) or 0.6 mM (closed symbols) copper sulfate. (B) Effect of copper on M. xanthus growth. WT (blue line) and ΔcorE (red line) strains were grown in the absence of the metal and diluted to an OD₆₀₀ of 0.05 into fresh CTT liquid media containing the indicated copper concentrations. The OD₆₀₀ was then monitored after 24 h of incubation. Error bars indicate standard deviations.