The role of directed protein evolution in synthetic biology
Directed evolution is now a well established technique for the improvement of enzyme properties, and for generating proteins, particularly for therapeutic use, that can bind tightly to a new target protein. Such techniques will also play a key role in the emergence of Synthetic Biology as a major route to harnessing complex biological systems that address the growing needs of a global society for better healthcare, sustainable energy, and sufficient food. The synthesis of pharmaceuticals, fuels and other chemicals, will increasingly rely on non oil-based feedstocks such as sustainable biomass. This will require novel metabolic pathways, containing specifically evolved enzymes, to be engineered into suitable host cells. By engineering a cell's proteins, it is also possible to engineer a cell with novel functions. Ambitions to create synthetic cells with entirely artificial, orthogonal or synthetic cell biology, including non-natural DNA, RNA, amino-acid, and protein analogues, will inevitably require extensive engineering of proteins using directed evolution. The early phases of this have already led to xeno-nucleic acid (XNA) synthesis capable itself of being used in a directed evolution process to produce novel aptamers.