Bacterial Expression System
Patent Information:
Filing Country: USA
Application No: 09/121286
Filing Date: 23 July 1998
Patent No: 6146848
Issue Date: 14 November 2000
Inventor 1: . Kat Hon, LAM
Inventor 2: Prof. Wan Keung, WONG

Bacillus subtilis has been widely used for extracellular production of native and homologous proteins. Based on the use of a synthetic expression/secretion cassette, a new bacterial expression system is developed and may be applied to produce heterologous proteins efficiently as secreted products. This bacterial expression system is particularly for the expression of heterologous proteins for use with gram-positive and gram-negative bacteria, particularly Bacillus subtilis and E. coli. It comprises of novel genetic constructs. Also provided is a novel promoter element. The novel expression cassette, Veg cassette, allows very high expression of heterologous proteins to be achieved in B. subtilis. The cassette may be cloned into a modified B. subtilis/E. coli shuttle vector pRB373M2 to form an expression/secretion vector named the veg vector. The application of the cassette has successfully promote efficient secretory production of two widely different heterologous proteins, an endoglucanase (Eng) of Cellulomonas fimi and human epidermal growth factor (hEGF) in B. subtilis. Moreover, the cassette was successfully used to express and secrete proteins that were found to be difficult to produce in B. subtilis, e.g. hEGF.
Potential Application   Advantage
- Production of secretory heterologous proteins in Bacillus subtilis and E. coli
- Production of large quantity of hormones, growth factors and peptide drugs
  1. High stability
2. High levels of extracellular products provided
3. Efficient production of protocols and clones of the two recombinant proteins (C. fimi Eng and hEGF)
4. Avoid the use of protease-deficient strains which are usually slow growing and difficult to handle
5. Render the heterologous gene cassette to be protected from the restriction of the host bacteria
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