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Updated: Jul 18, 2026
11:47
Residue-specific Incorporation of Noncanonical Amino Acids into Model Proteins Using an Escherichia coli Cell-free Transcription-translation System
Published on: August 1, 2016
Natural expansion of the genetic code
Alexandre Ambrogelly1, Sotiria Palioura, Dieter Söll
1Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, USA.
Nature Chemical Biology
|December 19, 2006
Summary
The genetic code, once thought fixed, is evolving. RNA structure, modification, and synthetase diversity reveal its dynamic nature, with new amino acids being incorporated.
Area of Science:
- Molecular Biology
- Genetics
- Evolutionary Biology
Background:
- The genetic code was historically considered a
- frozen accident,
- implying it was fixed and universal.
- Recent discoveries challenge this notion, suggesting a more dynamic and evolving system.
Purpose of the Study:
- To explore the evolutionary mechanisms shaping the genetic code.
- To investigate the roles of RNA components and aminoacyl-tRNA synthetases in code evolution.
- To examine evidence for codon reassignment and the incorporation of non-standard amino acids.
Main Methods:
- Analysis of RNA structure and modification in messenger RNA (mRNA) and transfer RNA (tRNA).
- Investigation of aminoacyl-tRNA synthetase diversity.
- Review of known codon reassignments in various organisms and subcellular organelles.
Main Results:
- RNA structure, modification, and aminoacyl-tRNA synthetase diversity play crucial roles in the genetic code's evolution.
- Codon reassignment is observed across different lineages and organelles, indicating the code is not immutable.
- The addition of selenocysteine and pyrrolysine to the standard 20 amino acids highlights the code's plasticity.
Conclusions:
- The genetic code is not a static entity but a dynamic system shaped by evolutionary pressures.
- The discovery of phosphoseryl-tRNA suggests potential for further discoveries of cotranslationally inserted modified amino acids.
- Understanding these evolutionary dynamics is key to deciphering the full complexity of the genetic code.
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