PubMed Health⌕ Search

Biomedical subjects

Jason W Chin

Publications and source records attributed to Jason W Chin.

6 recordsLinked to original sources
PubMed2003

An expanded eukaryotic genetic code.

We describe a general and rapid route for the addition of unnatural amino acids to the genetic code of Saccharomyces cerevisiae. Five amino acids have been incorporated into proteins efficiently and with high fidelity in response to the nonsense codon TAG. The side chains of these amino acids contain a keto group, which can be uniquely modified in vitro and in vivo with a wide range of chemical probes and reagents; a heavy atom-containing amino acid for structural studies; and photocrosslinkers for cellular studies of protein interactions. This methodology not only removes the constraints imposed by the genetic code on our ability to manipulate protein structure and function in yeast, it provides a gateway to the systematic expansion of the genetic codes of multicellular eukaryotes.

Amino Acids↗
PubMed2003

Progress toward an expanded eukaryotic genetic code.

Expanding the eukaryotic genetic code to include unnatural amino acids with novel properties would provide powerful tools for manipulating protein function in eukaryotic cells. Toward this goal, a general approach with potential for isolating aminoacyl-tRNA synthetases that incorporate unnatural amino acids with high fidelity into proteins in Saccharomyces cerevisiae is described. The method is based on activation of GAL4-responsive HIS3, URA3, or lacZ reporter genes by suppression of amber codons in GAL4. The optimization of GAL4 reporters is described, and the positive and negative selection of active Escherichia coli tyrosyl-tRNA synthetase (EcTyrRS)/tRNA(CUA) is demonstrated. Importantly, both selections can be performed on a single cell and with a range of stringencies. This method will facilitate the isolation of a range of aminoacyl-tRNA synthetase (aaRS)/tRNA(CUA) activities from large libraries of mutant synthetases.

Amino Acids↗
PubMed2002

Addition of p-azido-L-phenylalanine to the genetic code of Escherichia coli.

We report the selection of a new orthogonal aminoacyl tRNA synthetase/tRNA pair for the in vivo incorporation of a photocrosslinker, p-azido-l-phenylalanine, into proteins in response to the amber codon, TAG. The amino acid is incorporated in good yield with high fidelity and can be used to crosslink interacting proteins.

Azides↗
PubMed2002

Addition of a photocrosslinking amino acid to the genetic code of Escherichiacoli.

Benzophenones are among the most useful photocrosslinking agents in biology. We have evolved an orthogonal aminoacyl-tRNA synthetase/tRNA pair that makes possible the in vivo incorporation of p-benzoyl-l-phenylalanine into proteins in Escherichia coli in response to the amber codon, TAG. This unnatural amino acid was incorporated with high translational efficiency and fidelity into the dimeric protein glutathione S-transferase. Irradiation resulted in efficient crosslinking (>50%) of the protein subunits. This methodology may prove useful for discovering and defining protein interactions in vitro and in vivo.

Amino Acids↗
PubMed2002

A view to a kill: ligands for Bcl-2 family proteins.

Apoptosis is the essential process of programmed cell death that, in multicellular organisms, regulates development and maintains homeostasis. Defects in the apoptotic molecular machinery that result in either excessive or insufficient apoptosis are observed in a remarkably wide range of human disease, prompting intense interest in pro- and anti-apoptotic proteins as therapeutic targets. A number of recent reports have described the discovery of ligands for anti-apoptotic Bcl-2 family proteins by a variety of approaches, including computational, combinatorial and evolutionary strategies. Both the design of ligands and the exploration of their mechanisms of action have been greatly enhanced by recent high-resolution structure determinations of proteins from this family. Several of the newly discovered ligands promote apoptosis, and some do so even in the face of overexpressed anti-apoptotic Bcl-2 proteins. Ligands that overcome the protective effects associated with up-regulation of anti-apoptotic Bcl-2 proteins represent especially promising therapeutic leads.

Apoptosis↗