Incorporation of unnatural amino acids for synthetic biology.

The challenge of synthetic biology lies in the construction of artificial cellular systems. This requires the development of modular "parts" that can be integrated into living systems to elicit an artificial, yet programmed, response or function. The development of methods to engineer proteins bearing unnatural amino acids (UAAs) provides essential components that may address this challenge. Here we review the emerging strategies for incorporating UAAs into proteins with the endgame of engineering artificial cells and organisms.