In Vivo Biosynthesis and Direct Incorporation of Noncanonical Amino Acids into Proteins

Autonomous cells are engineered biological systems capable of biosynthesising and directly incorporating noncanonical amino acids (ncAAs) into proteins. These systems have the potential to extend the applicability of the genetic code to enable large-scale fermentative production of proteins carrying ncAAs. This work evaluates approaches for the generation of autonomous and semi-autonomous cells. Semi-autonomous cells rely on the external addition of a precursor, which is enzymatically converted in vivo to an ncAA that is directly incorporated. In contrast, autonomous cells have a metabolic system that produces and directly incorporates an ncAA in vivo. Through a critical evaluation of the state of the art, the reader is provided with an opinion on the future development of the field.