Bacterial expression vector for enhanced protein secretion

A bacterial expression vector for enhanced secretion of recombinant protein from a host bacterial cells, preferably, E. coli, comprising of:

• at least one secretory signal sequence;
• at least one gene expression cassette comprising of at least one inducible promoter, an RBS, DNA sequence encoding therecombinant protein, DNA sequence encoding an affinity tag, and at least one gene terminator, with the secretory signal sequence operably linked to the gene expression cassette, and the DNA sequence of the affinity tag operably linked to the DNA sequence of the recombinant protein;
• at least one bacterial ori gene sequence for replication of the vector in the host bacterial cell;
• and
• at least one DNA sequence for coding a selectable marker with a suitable promoter and a gene terminator sequence flanking the DNA sequence of the selectable marker,
• wherein,
• the secretory signal sequence is a combination of a) at least one DNA sequence encoding a signal sequence of genes selected from the group consisting of pelB, ompA, yebF, and ompF, and b) at least one DNA sequence encoding a carrier peptide, preferably, DNA sequence encoding truncated yebF;
• the DNA sequence encoding the truncated yebF belongs to the group consisting of Seq. ID 5 and Seq. ID 6;
• Seq. ID 5 encodes truncated yebF represented by Seq. ID 7;
• Seq. ID 6 encodes truncated yebF represented by Seq. ID 8;
• the DNA sequence Seq. ID 6 is synthesized by mutating Seq. ID 5, wherein, TGC codon at position 40 in Seq. ID 5 is mutated to GCG codon, to mutate Cys at position 14 of amino acid sequence represented by Seq. ID 7 to Ala at position 14 of amino acid sequence represented by Seq. ID 8;
• and
• the bacterial expression vector for enhanced secretion of recombinant protein is 6793 base pairs vector represented by Seq. ID 13.