Escherichia coli BL21(DE3) chromosome-based controlled intracellular processing system for fusion protein separation

A chromosome-based controlled intracellular processing system was constructed by integrating the TEV protease gene into the chromosome of E. coli BL21(DE3) with λ-Red recombineering. The system is highly efficient in processing maltose binding protein fusion protein; the separated protein could be purified to near homogeneity with Ni-NTA affinity chromatography.