Something about Protein Expression in Bacteria

Question

The first choice for the expression of recombinant proteins is typically E. coli. Production of proteins in this bacterial strain is well-established, fast and simple and usually provides high yields. Recent progress in the fundamental understanding of transcription, translation, and protein folding in E. coli, improved genetic tools had made this bacterium more valuable than ever for the expression of complex eukaryotic proteins. This is what I learned at http://www.creative-biolabs.org/bacterial-expression-systems-e-coli-bacillus.html.

 

CAn anyone tell me more about protein expression in bacteria? Everything will be helpful. 

 

 

Answer 1

Candy,

 

Certain eukaryotic proteins are not expressed in bacteria since either they are toxic or E. coli lacks the correct folding machinery to process the protein. If it is made then it is highly unstable and labile and is degraded right away before one can detect it. In such case, specific domains of proteins need to be expressed as fusion proteins to find out the domain that is resistant to bacterial expression and/or toxic or makes protein difficult to fold.

 

To delineate the function of other eukaryotic proteins, synthetic mRNA with an in-frame tag (Beta-galactosidase, luciferase etc. ) is injected in Xenopus (they have higher rate of transcription and translation) and protein synthesis is traced through known tag. Sometimes mRNA is driven by inducible promoter and injection is in one cell embryo (Zebrafish, Xenopus, mouse),  this is done  to find out at what stage the protein expression can be accomplished. Drosophila embryos are used as well.

 

In addition to bacteria, baculovirus system is also used for eukaryotic  protein expression when bacterial protein are unstable or hard to express.

 

Hope this helps, this is general and basic information and would vary for specific proteins.