Bacterial Expression Systems
1) Escherichia coli Excretion System
We have developed unique E. coli excretion systems using the Tac and LacUV5 cassettes, in conjunction with plasmid stabilizers for efficient production of recombinant proteins.
An E. coli LacUV5-cassette excretion system
LacUV5 Expression Cassette
Plasmid containing hEGF gene
2) Bacillus subtilis Secretion System
Another expression & secretion system is engineered in B. subtilis for efficient extracellular production of heterologous proteins. Regulatory cassettes containing transcriptional controls derived from the veg I promoter and the Staphylococcal protein A signal peptide are employed in this system.
There are many advantages of the extracellular approach over the intracellular one for the production of recombinant proteins.
- Correct folding to a functional native form – authentic and bioactive product
- Reduction of proteolysis, and thus higher product yields
- Reduction of contamination from unwanted proteins (e.g. endotoxin), and thus attainment of product with better quality
- Unwanted N-terminal methionine can be avoided
- Easy purification process and reduced production cost
- Suitable for large and industrial scale production
- Applicable for the production of all naturally secretory proteins
- Applicable for the production of mildly toxic proteins
- Continuous production possible