Traditional cell-based methods of expressing proteins are encumbered by the necessity to maintain viability of the cell line requiring tight control over multiple biochemical and biophysical parameters. Requirement of the intact cell wall also prevents the efficient incorporation of non-natural amino acids (nnAA) due to the lack of endogenous transport mechanisms in these systems. The Xpress CF platform overcomes these significant limitations by separating the precise cellular machinery required for transcription, translation, and energy production into an E.coli-derived Extract capable of continuous oxidative phosphorylation. The simple addition of DNA plasmid, coding for nnAA if applicable, and T7 polymerase to the Extract triggers protein production and is sustained with glucose, an inexpensive energy source. This cell-free system is easily manipulated to facilitate optimal protein folding by altering pH, temperature, redox potential, ionic strength, etc to identify an optimal set of conditions to produce antigenic proteins in the desired conformation. Proteins can be rapidly engineered and optimized by producing multiple variants in parallel in 96-well plates from DNA libraries.
Industrialized & Scaled
The seminal invention underpinning the Xpress CF platform was the creation of engineered E.coli-derived proprietary Extracts containing fully functional oxidative phosphorylation machinery in inverted membrane vesicles and orthogonal tRNA capable of catalyzing nnAA incorporation. This innovation enables the Extracts to regenerate high energy phosphates required for protein translation and nnAA incorporation, dramatically reducing production cost and permitting the use of industrial sized reaction vessels and longer manufacturing run times than previously thought possible. The Xpress CF system routinely produces g/L of complex proteins in 8-10 hours and scales linearly from bench to large-scale GMP production. The protein of interest is produced at high yield and the absence of cellular debris combine to simplify downstream purification, further enhancing production efficiency.