Protein Expression by Expansion of the Genetic Code

Abstract

The Genetic Code consists of 64 three-base codons that code for 20 amino acids and three stop signals. Recent engineering of the cell's protein synthesis machinery has allowed unnatural amino acids to be encoded in the genetic code of prokaryotic and eukaryotic organisms. Importantly, the approaches discussed add unnatural amino acids to the genetic code, without detracting from the cell's ability to incorporate the common 20 amino acids into proteins. Here we discuss the intellectual and practical strategies that have been employed in the challenging, but ultimately successful expansion of the genetic code. We also discuss the emerging applications of expanded genetic codes in solving basic biological and biophysical problems and in creating a new synthetic biology.