A chemical toolkit for proteins — an expanded genetic code

  title={A chemical toolkit for proteins — an expanded genetic code},
  author={Jianming Xie and Peter G. Schultz},
  journal={Nature Reviews Molecular Cell Biology},
  • J. XieP. Schultz
  • Published 23 August 2006
  • Biology, Chemistry
  • Nature Reviews Molecular Cell Biology
Recently, a method to encode unnatural amino acids with diverse physicochemical and biological properties genetically in bacteria, yeast and mammalian cells was developed. Over 30 unnatural amino acids have been co-translationally incorporated into proteins with high fidelity and efficiency using a unique codon and corresponding transfer-RNA:aminoacyl–tRNA-synthetase pair. This provides a powerful tool for exploring protein structure and function in vitro and in vivo, and for generating… 

A facile system for encoding unnatural amino acids in mammalian cells.

A shuttle system has been developed to genetically encode unnatural amino acids in mammalian cells using aminoacyl-tRNA synthetases (aaRSs) evolved in E. coli, making possible the selective incorporation of this unnatural amino acid into proteins.

Designer proteins: applications of genetic code expansion in cell biology

Designer amino acids, beyond the canonical 20 that are normally used by cells, can now be site-specifically encoded into proteins in cells and organisms. This is achieved using 'orthogonal'

Genetic incorporation of unnatural amino acids into proteins in mammalian cells

A general approach that allows unnatural amino acids with diverse physicochemical and biological properties to be genetically encoded in mammalian cells to facilitate the introduction of biological probes into proteins for cellular studies and may ultimately facilitate the synthesis of therapeutic proteins containing unnatural amino acid in mammaliancells.

Ribosome evolution for two artificial amino acids in E. coli.

Evolution of amber suppressor tRNAs for efficient bacterial production of proteins containing nonnatural amino acids.

Open in a separate window Regions of the M. jannaschii tyrosyl tRNACUA thought to interact with elongation factor Tu were randomized, and the resulting tRNA libraries were subjected to in

Reprogramming the Genetic Code

These routes to unnatural polymer synthesis and evolution are already facilitating the study of cellular processes including protein interactions, protein conformational changes, posttranslational modification biology, and the kinetics of protein transport and cell signaling with a new level of molecular precision.

Enhancing Protein Stability with Genetically Encoded Noncanonical Amino Acids.

It is shown that substitution of Phe 21 with ( p-benzoylphenyl)alanine (pBzF), increases the melting temperature of E. coli metA by 21 °C, and shows that an expanded genetic code can provide unique solutions to the evolution of proteins with enhanced properties.

Site-Specific Incorporation of Unnatural Amino Acids into Escherichia coli Recombinant Protein: Methodology Development and Recent Achievement

The latest progress made to enhance nonsense suppression in E. coli is described with the emphasis on the improved expression vectors encoding for an orthogonal aa-RA/tRNA pair, enhancement of a a-RS and suppressor tRNA efficiency, the evolution of Orthogonal EF-Tu and attempts to reduce the effect of RF1.

Incorporation of unnatural amino acids for synthetic biology.

The emerging strategies for incorporating UAAs into proteins with the endgame of engineering artificial cells and organisms are reviewed.

Expanding the Genetic Code of an Animal

The genetic code of a multicellular animal, the nematode Caenorhabditis elegans, is expanded to allow for the site-specific incorporation of unnatural amino acids into proteins.



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 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.

Expanding the Genetic Code of Escherichia coli

A unique transfer RNA/aminoacyl-tRNA synthetase pair has been generated that expands the number of genetically encoded amino acids in Escherichia coli and should provide a general method for increasing the genetic repertoire of living cells to include a variety of amino acids with novel structural, chemical, and physical properties not found in the common 20 amino acids.

A genetically encoded photocaged amino acid.

Using a novel genetic selection, a series of synthetase mutants are identified that selectively charge the amber suppresor tRNA with the C8 amino acid, alpha-aminocaprylic acid, and the photocaged amino acids, o-nitrobenzyl cysteine, allowing them to be inserted into proteins in yeast in response to the amber nonsense codon, TAG.

Efficient incorporation of unnatural amino acids into proteins in Escherichia coli

A single-plasmid system for the efficient bacterial expression of mutant proteins containing unnatural amino acids at specific sites designated by amber nonsense codons is developed.

Adding amino acids with novel reactivity to the genetic code of Saccharomyces cerevisiae.

Using a novel genetic selection, we have identified a series of mutants of the E. coli tyrosyl-tRNA synthetase that selectively charge an amber suppressor tRNA with p-(propargyloxy)phenylalanine and

Probing Protein Structure and Function with an Expanded Genetic Code

A general biosynthetic method has been developed which makes it possible to site-specifically incorporate unnatural amino acids with novel properties into proteins, used to study the stability, specificity, and catalytic properties of a number of proteins.

Generation of a bacterium with a 21 amino acid genetic code.

A completely autonomous bacterium with a 21 amino acid genetic code that can biosynthesize a nonstandard amino acid from basic carbon sources and incorporate this amino acid into proteins in response to the amber nonsense codon is generated.

The genetic incorporation of a distance probe into proteins in Escherichia coli.

It was shown that pNO2-Phe efficiently quenches the intrinsic fluorescence of Trp in a distance-dependent manner in a model GCN4 basic region leucine zipper (bZIP) protein, which should be a useful biophysical probe of protein structure and function.

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.