Twin-arginine translocation in
Described herein are methods to enhance protein secretion in a host cell. In preferred embodiment, the host cell is a gram-positive microorganism such as a Bacillus . In another preferred embodiment, the host cell is a gram-negative microorganism. Preferably the gram-negative microorganism is an Escherichia coli or a member of the genus Pantoea . Protein secretion may be enhanced by the overexpression of protein components of the Tat pathway. Alternatively, secretion of foreign proteins can be selectively enhanced by forming a chimeric polypeptide comprising a tat signal sequence and the protein of interest. In a preferred embodiment, the tat signal sequence is selected from phoD or LipA.
1. An isolated chimeric polypeptide comprising (i) a Bacillus subtilis LipA secretion signal peptide and (ii) a heterologous polypeptide.
2. The chimeric polypeptide of claim 1 , wherein said heterologous polypeptide is not naturally associated with a secretion signal peptide.
3. The chimeric polypeptide of claim 1 , wherein the heterologous polypeptide is an enzyme.
4. The chimeric polypeptide of claim 3 , wherein the enzyme is selected from the group consisting of a protease, cellulase, amylase, lipase, and hydrolase.
5. The chimeric polypeptide of claim 4 , wherein the enzyme is a protease.
6. The chimeric polypeptide of claim 4 , wherein the enzyme is a cellulase.
7. The chimeric polypeptide of claim 4 , wherein the enzyme is an amylase.
8. The chimeric polypeptide of claim 4 , wherein the enzyme is a lipase.
9. The chimeric polypeptide of claim 4 , wherein the enzyme is a hydrolase.
10. The chimeric polypeptide of claim 2 , wherein the heterologous polypeptide is an enzyme.
11. The chimeric polypeptide of claim 10 , wherein the enzyme is selected from the group consisting of a protease, cellulase, amylase, lipase, and hydrolase.
12. The chimeric polypeptide of claim 11 , wherein the enzyme is a protease.
13. The chimeric polypeptide of claim 11 , wherein the enzyme is a cellulase.
14. The chimeric polypeptide of claim 11 , wherein the enzyme is an amylase.
15. The chimeric polypeptide of claim 11 , wherein the enzyme is a lipase.
16. The chimeric polypeptide of claim 11 , wherein the enzyme is a hydrolase.