Expanding the genetic code--TSRI scientists synthesize 21-amino-acid...( r the new amino acid in that place giv...)

Using this method, Schultz and his colleagues last year incorporated the unusual amino acid O-methyl-L-tyrosine into proteins with fidelity greater than 99 percent, which is close to the translation fidelity of natural amino acids. They have since demonstrated the ability to incorporate several other unusual amino acids into proteins, including the unusual amino acid p-aminophenylalanine, which is described in the latest report.

Now, by adding "plasmids"--circular, self-contained pieces of DNA that express the metabolic genes necessary for making p-aminophenylalanine--they have given the bacteria the ability to synthesize their own unusual amino acids and insert them into any protein coded for by an mRNA containing a UAG codon.

With a fully autonomous 21 amino acid bacterium, they can also compare this unique form of life to an analogous bacterium that uses only the 20 natural amino acids and see how their evolutionary fitness and survivability compare.

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Contact: Jason Bardi
jasonb@scripps.edu
858-784-9254
Scripps Research Institute
14-Jan-2003