Expanding the Genetic Code of Escherichia coli

  title={Expanding the Genetic Code of Escherichia coli},
  author={Lei Wang and Ansgar Brock and Brad Herberich and Peter G. Schultz},
  pages={498 - 500}
A unique transfer RNA (tRNA)/aminoacyl-tRNA synthetase pair has been generated that expands the number of genetically encoded amino acids in Escherichia coli. When introduced into E. coli, this pair leads to the in vivo incorporation of the synthetic amino acid O-methyl-l-tyrosine into protein in response to an amber nonsense codon. The fidelity of translation is greater than 99%, as determined by analysis of dihydrofolate reductase containing the unnatural amino acid. This approach should… 
An Expanded Eukaryotic Genetic Code
A general and rapid route for the addition of unnatural amino acids to the genetic code of Saccharomyces cerevisiae is described, providing a gateway to the systematic expansion of the genetic codes of multicellular eukaryotes.
Adding amino acids to the genetic repertoire.
Expanding the Genetic Code
This methodology provides a powerful tool both for exploring protein structure and function in vitro and in vivo and for generating proteins with new or enhanced properties.
An expanding genetic code.
An expanded genetic code with a functional quadruplet codon.
This work suggests that neither the number of available triplet codons nor the translational machinery itself represents a significant barrier to further expansion of the genetic code.
Expanding the genetic code for biological studies.
Protein Expression by Expansion of the Genetic Code
The intellectual and practical strategies that have been employed in the challenging, but ultimately successful expansion of the genetic code are discussed.
Incorporation of nonnatural amino acids into proteins.
The genetic code is established by the aminoacylation of transfer RNA, reactions in which each amino acid is linked to its cognate tRNA that, in turn, harbors the nucleotide triplet (anticodon)
Expanding the genetic code.
Using this strategy, the genetic code of Escherichia coli has been expanded to incorporate unnatural amino acids with a fidelity rivaling that of natural amino acids.


A New Orthogonal Suppressor tRNA/Aminoacyl‐tRNA Synthetase Pair for Evolving an Organism with an Expanded Genetic Code
This work has introduced a new orthogonal suppressor tRNA/aminoacyl-tRNA synthetase pair in E. coli derived from the Saccharomyces cerevisiae tRNAAsp and aspartyl-t RNA Synthetase, and the in vitro and in vivo characteristics of this pair were determined.
Ribosome-mediated incorporation of a non-standard amino acid into a peptide through expansion of the genetic code
A new technology for incorporating non-standard amino acids into polypeptides by ribosome-based translation is described, which compares favourably with another recently described approach in which the genetic code is simply rearranged to recruit stop codons to play a coding role.
Progress toward the evolution of an organism with an expanded genetic code.
  • D. R. Liu, P. Schultz
  • Biology, Chemistry
    Proceedings of the National Academy of Sciences of the United States of America
  • 1999
A rapid nonradioactive screen for unnatural amino acid uptake was developed and applied to a collection of 138 amino acids, and the majority of glutamine and glutamic acid analogs under examination were found to be uptaken by E. coli.
Escherichia coli thymidylate synthase: amino acid substitutions by suppression of amber nonsense mutations.
By using site-directed oligonucleotide mutagenesis, amber nonsense stop codons (5'-TAG-3') have been introduced at 20 sites in the Escherichia coli thymidylate synthase gene. By transforming the thyA
Site-directed mutagenesis with an expanded genetic code.
A biosynthetic method has been developed that makes possible the site-specific incorporation of a large number of amino acids and analogues within proteins to address detailed structure-function questions.
A New Functional Suppressor tRNA/ Aminoacyl-tRNA Synthetase Pair for the in Vivo Incorporation of Unnatural Amino Acids into Proteins
This approach involves the generation of a suppressor tRNA/aminoacyl-tRNA synthetase (tRNACUA/aaRS) pair that is orthogonal to Escherichia coli endogenous tRNAs and insights into the development of additional pairs are provided.
Quadruplet codons: implications for code expansion and the specification of translation step size.
Evidence is presented which suggests that when there is a purine base at position 32 of this 5' flanking tRNA, it influences decoding of the UAGA quadruplet.
A Mutant Escherichia coli Tyrosyl-tRNA Synthetase Utilizes the Unnatural Amino Acid Azatyrosine More Efficiently than Tyrosine*
Kinetic analysis of aminoacyl-tRNA formation by the wild-type and mutated F130S TyrRS enzymes showed that the specificity for azatyrosine, measured by the ratios ofk cat/K m for tyrosine and the analogue, increased from 17 to 36 as a result of the F 130S mutation.
A general method for site-specific incorporation of unnatural amino acids into proteins.
The ability to selectively replace amino acids in a protein with a wide variety of structural and electronic variants should provide a more detailed understanding of protein structure and function.
Editing of errors in selection of amino acids for protein synthesis.
The availability of X-ray crystallographic structures of some synthetases, combined with site-directed mutagenesis, allows insights into molecular details of the extraordinary selectivity of synthetase, including the editing function.