Da Yu Protein Sciences – Protein Expression
Da Yu Protein Sciences has expertise in the expression of recombinant proteins in Escherichia coli. To assist clients with optimizing the expression of their protein we employ a small-scale screening strategy. We utilize a three-pronged approach to protein expression consisting of expression plasmids, E. coli strains, and growth conditions. Da Yu Protein Sciences has assembled a collection of proprietary expression plasmids to assist clients with protein production. These expression plasmids, or a client-provided plasmid, are transformed into one or more of our E. coli strains. Transformed cells are grown in different media under different conditions to assess protein expression. Once the optimal system and conditions have been identified for the expression of a client’s protein we can perform a small-scale production run by growing the optimized E. coli culture to high-cell density utilizing our benchtop Fermentations.
Perseus™ Expression Technology
Da Yu Protein Sciences is also developing its own novel protein production platform based on our proprietary and patented Perseus™ Expression Technology. Perseus™ Expression Technology leverages the favorable characteristics associated with recombinant protein production in E. coli, but it lacks many of its disadvantages. Perseus™ Expression Technology permits designed manipulations of the bacterial cytoplasm such that it is transformed into an environment conducive to proper protein folding. Improper disulfide formation, misfolding, aggregation and inclusion body formation can potentially be minimized under proper empirically-determined conditions. When bacteria 
genetically-modified with Perseus™ Expression Technology are treated with a chemical switch the bacteria cease to grow and the majority of the cell's metabolic activity shifts to recombinant protein production. This unique expression system can utilize the protein synthesis machinery of any desirable E. coli strain. Strains such as BL21, HB101, MM294, W3110 and others utilizing common promoters (e.g., lac, trp, tac, etc.) are all adaptable to Perseus™ Expression Technology. Da Yu Protein Sciences has developed prototype E.coli strains with Perseus™ Expression Technology and these strains are available for client assessment or licensing.
In Vitro Protein Synthesis
Perseus™ Expression Technology is analogous to a scalable in vitro protein synthesis system that does not require the preparation of separate critical reagents such as cytoplasmic extracts and enzyme components. Perseus™ Expression Technology is applicable to any scale consistent with E. coli fermentation and it does not require extraordinary infrastruture. Perseus™ Expression Technology potentially offers clients the following advantages:
- Scalability with low operating costs
- Inclusion body reduction
- Proper protein folding without using fused protein tags
- Economical and efficient incorporation of radioactive and non-radioactive isotopes
- The incorporation of non-natural amino acids
- The production of toxic recombinant proteins
- The production of membrane proteins
- Biosimilar protein production
- Small molecule drug screening
Organizations interested in learning more about our E. coli protein expression capabilities or applying Perseus™ Expression Technology to their programs are encouraged to Contact Us.