Protein Expression

GenWay offers protein expression services include

  • Escherichia coli
  • Mammalian cells (293 or CHO)
  • Yeast (Pichia or Saccharomyces cerevisiae)
  • Insect cells (Baculovirus)

GenWay has a diverse protein expression platform that combines the technologies of bioinformatics, protein domain analysis, gene codon optimization, protein fusion, and protein expression in different host cells. The multi-tiered platform for recombinant protein production depicted in Figure 1 allows GenWay to produce soluble and functional proteins. In particular, GenWay has the capability and vector systems for expression of difficult-to-express proteins such as proteases, kinases, and membrane proteins.

 

Figure 1. GenWay's protein production platform.

To meet the demands of producing recombinant proteins in a soluble and/or functional form, multiple expression systems that employ different host cells are designed and constructed to form a multi-functional expression platform. Recombinant proteins can be produced through the 4-host type system depicted above according to the requirements of the end product and other factors such as solubility, post-translational modifications, functionality, timeline, and cost consideration. The multi-tired platform is designed to overcome difficulties of protein expression in a particular host cell system and enhance the success rate of production.

The multi-tiered system can be applied for providing solutions to protein expression. Table 1 provides a general comparison of the features and advantages of each expression system.

 

Table 1. Comparison of Expression Systems
Characteristics E. coli Yeast Insect cells Mammalian cells
Cell Growth Rapid (30 Min) Rapid (90 Min) Slow (18-24 H) Slow (24 H)
Complexity of Growth Medium Minimum Minimum Complex Complex
Cost of Growth Medium Low Low High High
Expression Level High Low - High Low - High Low - Moderate
Extracellular Expression Secretion to Periplasm Secretion to Medium Secretion to Medium Secretion to Medium
Protein Folding Refolding Usually Required Refolding May Be Required Proper Folding Proper Folding
N-linked Glycosylation None High Mannose Simple, No Sialic Acid Complex
O-linked Glycosylation No Yes Yes Yes
Phosphorylation No Yes Yes Yes
Acetylation No Yes Yes Yes
Acylation No Yes Yes Yes
gamma-Carboxylation No No No Yes
Yield (mg) (per liter culture ) 50-500 10-200 10-200 0.1-100
Success Rate (%) (soluble or functional) 40-60 50-70 50-70 80-95
Project Cost Low Low Middle High
Recommended Use Antigen protein, Protein standards, Functional proteins Proteins with glycosylation, Vaccine, Secreted form, Alternative to insect cell system Proteins with glycosylation, Assay standards, Secreted form, Alternative to yeast system Functional study, PTM study, Assay standards, Characterization
Advantage Simple, robust, lowest cost, highest yield Simple, low cost, good for certain proteins Relatively higher yield, better PTM Natural protein configuration, best PTM
Disadvantage Least PTMa Longer time, less PTM Longer time, higher cost Highest cost, lower yield

 

a PTM = Post-Translational Modification such as glycosylation.

Host system selection is done in close collaboration with the client depending on the following factors:

  • Either protein is secreted or intracellular
  • Hydrophobicity of the protein
  • Required purity and quantity
  • Glycosylation and other PTM
  • Cellular localization (membrane or non-membrane)
  • Functional activity and other specifications
  • Large-scale cGMP/cGLP manufacturing requirement
  • Budget allowance

The project design is prepared through extensive bioinformatics analysis, literature review, internal discussions, discussions with customers, and consultation with leaders in the protein expression field. For more detailed service information, please see the service description pages in protein expression.