System for expressing and transporting recombinant perplasmid escherichid coli proteins by the Tat secretion pathway.

The present invention relates to an expression vector containing a signal peptide that utilizes the Tat secretion pathway as an alternative to the Sec secretion system for the transport of cytokinins and other proteins of biotechnological interest into the periplasm of Escherichia coli. The novel part of this invention consists in using the mutated penicillin acylase signal peptide (SPpac) fused to the synthetic human interferon-? gene (inf.-?) for protein transport into the periplasm of Escherichia coli via Tat. The mutated SPpac contains the NdeI site at the 5' end, containing in the expression vector pEMR, and at the 3' end the tryptophan codon is changed to the serine codon, thereby generating the Hind III restriction site. The Leucenia and Alanine codons are modified to generate the NheI site. This generates two restriction sites for cloning and gene-phase fusion of homologous or heterologous proteins. Currently, there are no commercial vectors available for the expression and transport of proteins using signal peptides of the Tat transport pathway.