Protein Synthesis: Twenty Three Amino Acids and Counting
The genetic code can be interpreted during translation as 21 amino acids and three termination signals. Recent advances at the interface of chemistry and molecular biology are extending the genetic code to allow assignment of new amino acids to existing codons, providing new functional groups for protein synthesis.
Ibba, M., Stathopoulos, C. and Söll, D. (2001) Protein synthesis: Twenty three amino acids and counting. Curr. Biol. 11, R563-R565. https://doi.org/10.1016/s0960-9822(01)00344-x