Fig. 2.

Optimization of the core region of the P_ylb promoter. a the core regions of the P_ylb promoter were changed to corresponding consensus sequence. The nucleotides in bold italic indicate mutated sequences. b The BgaB expression level under the control of P_ylb derivatives. c SDS-PAGE analysis of the BgaB expression. Equal amounts (30 μg) of total protein were loaded into each lane. The band corresponding to BgaB was marked. All cultures were grown in triplicate, and each experiment was performed at least twice. Error bars indicate standard deviations. CK represents the intracellular protein of strain WB800