Cell-free protein synthesis (CFPS) methodology offers the possibility to produce proteins that would be difficult or even impossible to synthesize in cell-based systems. These so-called “difficult-to-express proteins” include membrane proteins, but also cytotoxic proteins (toxic cancer therapeutics, antimicrobial peptides/proteins and toxins), vaccines, antibodies and proteins containing non-standard amino acids [1]. Cell-free systems are, also, advantageous for the synthesis of proteins with biased coding sequences or with defined post-translational modifications, for the ones that require chaperones or specific chemical environments and even for the synthesis of virus-like particles and bacteriophages.
