MICROBIAL PROTEIN EXPRESSION SYSTEM

摘要

The present invention provides bacterial strains for secretion of soluble biologically active recombinant heterologous proteins into periplasm or on a surface/into a cultivation medium of bacteria. The invention exploits the secretion system of Gram-negative bacteria including periplasmic chaperones and usher/secretin proteins. For accomplishing the aim, the bacterial strain s simultaneously express the fusion protein (signal peptide)-(mature heterologous protein)-(subunit of a bacterial surface structure, Caf1), periplasmic chaperone specific for the subunit, and outer membrane usher/secretin protein specific for the subunit. Secretion of fusion protein s: (signal peptide of Caf1)-(mature human IL-1.beta.)-(mature Caf1), (signal peptide of Caf1)-(mature human GM-CSF)-(mature Caf1), and (signal peptide of Caf1)-(mature human IL-1ra)-(mature Caf1) that were expressed in Escherichia coli simultaneously with the periplasmic chaperone CaflM and the usher/secretin protein CaflA are examples of the use of the invention.