DnaK/DnaJ supplementation improves the periplasmic production of human granulocyte-colony stimulating factor in Escherichia coli.

Human granulocyte-colony stimulating factor (hG-CSF) can be efficiently synthesized in E. coli as a fusion to a quimeric signal peptide, but this fusion is only partially exported to the periplasm. We have studied the effects of supplementing the host content in chaperonins on the secretion of prehG-CSF in E. coli. We have found that the DnaK/DnaJ chaperonin system improves the secretion of this recombinant protein. This improvement correlates with an increase in the solubility of the precursor. Only a small fraction of the mature protein is released from the periplasm by an osmotic shock.