Increasing Protein Expression
“In protein therapeutics, there are often difficulties in fusing proteins together or adding linkers, including making the protein inexpressable in E. coli. We helped a customer express a fused antibody in E. coli. They had a construct with low expression, and our technology, Translational Engineering™, significantly increased the expression,” states Alan Carter, svp, business development at CODA Genomics (www.codagenomics.com).
The main thing that drives antibody research, adds Joseph Kiddel, Ph.D., vp of research, is to work with a protein in the lab that has some desired type of binding characteristics. “When you first start working with a gene, it’s far from optimization,” notes Dr. Kiddel. “The more work you do to optimize binding, the more you tend to wander away from the gene sequences that express well. We go back and reoptimize the gene by identifying the translation control signals that might be a problem in providing a high yield of the protein.”
The result is a domesticated gene that is easy to work with in the lab and expresses a lot of protein. If protein yield is increased in the early stages, Dr. Kiddel explains, this makes other processes like purification and fermentation easier. Also, since it’s known how the gene was created, it provides the customer with IP position on an optimized gene that may be superior to the original gene.
Developed at University of California, Irvine, Translational Engineering is based on ribosomal movement along mRNA. “As a ribosome moves along, it periodically reaches a signal that tells it to slow down,” explains Dr. Kiddel. “If your goal is to make a lot of protein, that may not be what you want it to do. These signals vary when you move from one organism to another. Particularly if you are moving a human antibody into E. coli, the place where the ribosome would normally pause has changed. This is why there are so many problems getting antibodies to express in E. coli.
“Our technology is aimed at adapting genes so they express better in E. coli,” says Dr. Kiddel, adding that the company is working to increase understanding of how the biology of translation control applies to each protein family.