A novel, cheap and effective fusion expression system for the production of recombinant proteins.

To develop faster, less expensive methods for expression and purification of proteins, the annexin B1-intein fusion expression system was constructed. The interest proteins fused to the annexin B1-intein tag were purified in a single-step method based on the Ca(2+)-binding activity of annexin B1, and the annexin B1-intein fusion tag was removed based on the self-cleaving activity of the intein. Moreover, we found that in some cases, fusion to annexin B1 can promote the solubility of heterologous proteins. The production of soluble and highly active of interleukin-2 and low-molecular single-chain urokinase in our results proved that the system was a novel, cheap and effective fusion expression system for the production of valuable soluble recombinant proteins in Escherichia coli.