FIGURE 7.
The AccRD60E protein acts as a constitutive repressor of the PN promoter. A, effect of the AccRD60E protein on the activity of the PN promoter in E. coli AFMCPN cells that contain a chromosomal PN::lacZ fusion. Cells harboring a plasmid expressing the AccRD60E (pIZAccRD60E), AccR (pIZAccSR), or a cognate vector control (pIZ1016) (C), were grown anaerobically in glycerol-containing minimal medium until mid-exponential phase. Graphed values of β-galactosidase activities (in Miller units) are the average from three independent experiments ± S.D. (error bars). B, anaerobic growth of Azoarcus sp. CIBΔaccR (triangles) and Azoarcus sp. CIBΔaccR harboring pIZAccRD60E (squares) in minimal medium containing 3 mm benzoate as the sole carbon source.