Best Practices: Selecting an Expression System

Multiple cells with dividing cells in foreground. Proteos recombinant protein.

Proteos is an industry leader in the production of high-quality recombinant proteins from multiple expression platforms. One of the first variables to consider when producing recombinant proteins is the optimal expression system.

The structural complexity of the protein of interest provides clues for selecting an expression system. Simple proteins with a single structural domain and no essential post-translational modifications (PTMs) may express well in bacterial cells. However, proteins with multiple structural domains and PTMs may be insoluble in bacteria. Insect or mammalian cell expression systems are more suitable for expression of complex eukaryotic proteins. Insect cells possess most of the eukaryotic PTM machinery for protein folding and cellular trafficking. However, mammalian cells are the best choice when conservation of PTMs is critical for the protein’s structure and function.

In addition to structural complexity, it is important to consider the downstream use for the recombinant protein when selecting an expression system. Proteins that express well in bacterial cells can be used for in vitro experiments that are not adversely affected by endotoxin, including crystallization, binding studies, and biochemical assays. Proteins produced in eukaryotic cells can often also be used for these in vitro assays as well as for applications requiring low endotoxin, such as functional cell-based assays and in vivo studies.

Proteos offers bacterial, insect, and mammalian cell expression systems for production of recombinant proteins. Contact us today to discuss which expression system would be best for your specific project needs. Our next Best Practices blog will focus on generating multiple constructs for production of a novel recombinant protein.

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