Numerous approaches to optimize and enhance production of recombinant proteins in heterologous hosts are known and offered by a plethora of companies. These strategies primarily involve redesign of gene sequences, targeted to optimize the initiation step of protein synthesis and reduce possible obstacles to translation elongation that might be related to mRNA secondary structure and/or the use of different codon biases (1).
The conventional wisdom is that the codon adaptation index (CAI) (2) may serve as the predictor of the likelihood of success of heterologous gene expression. High CAI values were suggested to serve as indicators of high protein expression levels (3). The approach (which utilizes substitution of the majority of infrequent codons by the synonymous frequent ones targeted to inflate the CAI) has been widely used by many companies for optimization of heterologous protein expression, but only partial success has been achieved. Very often this approach results in surprisingly low protein expression levels and leads to insoluble protein aggregates. Moreover, even when proteins expressed in heterologous or homologous hosts remained soluble, they were not necessarily natively folded.
Recent evidences suggest that synonymous codons and, specifically, rare synonymous codons play an extremely important role in protein expression, export (secretion) and folding (4-6).
DAPCEL Inc utilizes unique Two-Layered DAPCEL™ RC (Rare Codon) Gene Optimization strategy for gene redesign that takes into account the importance of rare codons and overall kinetics of protein translation guided by synonymous codon usage for protein production and co-translational protein folding. This approach results in high yields of correctly folded soluble proteins expressed in any desired host.
1. Sørensen, H.P. and Mortensen, K.K. (2005) J. Biotechnol. 115, 113-128.
2. Sharp, P.M. and Li, W.H. (1987) Nucleic Acids Res. 15, 1281-1295.
3. Gustafsson, C., Govindarajan, S. and Minshull, J. (2004) Trends Biotechnol. 7, 346-353.
4. Komar, A.A. (2009) Trends Biochem Sci. 34, 16-24.
5. Zalucki, Y.M., Beacham, I.R. and Jennings, M.P. (2009) Trends Microbiol. 17, 146-150.
6. Komar, A.A. (2016) Top Med Chem, 2, 1-17.