Recombinant proteins, Bacillus

The host bacteria used for production of recombinant proteins are usually E. coli, or Bacillus subtilis they may express proteins at 1 % to over 50% of the cellular protein, depending on such variables as the source, promoter structure, and vector type. Generally the proteins are expressed intracellularly, but leader sequences for excretion may be included. In the latter case, the protein is generally excreted into the periplasmic space, which limits the amount that can be produced. Excretion from grampositive species such as B. subtilis sends the product into the culture medium, with little feedback limitation on total expression level. 

In addition to the limited number of expressed genes, bacteria feature a highly reproductive cycle but no cell nucleus, no organelles for compartmentation, no cell-to-cell communication as in tissues, and quite a straightforward metabolism. Favored bacterial systems for production of recombinant proteins are various strains of E. coli, Bacillus, and Pseudomonas. Non-bacterial options such as yeast or mammalian cells are discussed briefly later in this chapter. 

Systems Biology of Recombinant Protein Production in Bacillus megaterium... 

Tools for Recombinant Protein Production with Bacillus megaterium. 136... 

Du C, Chan W C, McKeithan T W, et al. (2005). Surface display of recombinant proteins on Bacillus thuringiensis spores. Appl. Environ. Microbiol. 71 3337-3341. 

Morimoto, T. et al (2008) Enhanced recombinant protein productivity by genome reduction in Bacillus subtilis. DNA Res., 15 (2), 73-81. 

Otenhoff, T.H., Kale, A.B., VanEmbden, J.D.A., Thole, J.E.R., Kiessling, R. (1988). The recombinant 65-kD heat shock protein of Mycobacterium bovis bacillus calmette guerin/M. tuberculosis is a target molecule for CD4 + cytotoxic T lymphocytes that lyse human monocytes. J. Exp. Med. 168, 1947-1952. 

Subtilisins are a class of related serine endo proteases produced by members of the Bacillus genus. The B.amvloliauefaciens subtilisin (BPN ) is well-characterized with regard to its DNA sequence 4 protein sequence (5), X-ray crystal structure (6) and kinetic properties (7). With this wealth of information available, BPN was chosen as the model enzyme for our recombinant approach. 

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