Recoding the Genetic Code with Selenocysteine

Selenocysteine (Sec) is naturally incorporated into proteins by recoding the stop codon UGA. Sec is not hardwired to UGA, as the Sec insertion machinery was found to be able to site‐specifically incorporate Sec directed by 58 of the 64 codons. For 15 sense codons, complete conversion of the codon me...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2014-01, Vol.53 (1), p.319-323
Main Authors: Bröcker, Markus J., Ho, Joanne M. L., Church, George M., Söll, Dieter, O'Donoghue, Patrick
Format: Article
Language:English
Subjects:
Escherichia coli
Formate dehydrogenase
genetic code
Genetic Code - genetics
Human
Humans
Information storage
Insertion
Machinery
Plugs
Protein Biosynthesis
Proteins
Recombinant
Reductases
RNA
selenocysteine
Selenocysteine - genetics
Selenocysteine - metabolism
sense codon recoding
synthetic biology
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Summary:Selenocysteine (Sec) is naturally incorporated into proteins by recoding the stop codon UGA. Sec is not hardwired to UGA, as the Sec insertion machinery was found to be able to site‐specifically incorporate Sec directed by 58 of the 64 codons. For 15 sense codons, complete conversion of the codon meaning from canonical amino acid (AA) to Sec was observed along with a tenfold increase in selenoprotein yield compared to Sec insertion at the three stop codons. This high‐fidelity sense‐codon recoding mechanism was demonstrated for Escherichia coli formate dehydrogenase and recombinant human thioredoxin reductase and confirmed by independent biochemical and biophysical methods. Although Sec insertion at UGA is known to compete against protein termination, it is surprising that the Sec machinery has the ability to outcompete abundant aminoacyl‐tRNAs in decoding sense codons. The findings have implications for the process of translation and the information storage capacity of the biological cell. The selenocysteine insertion machinery was engineered to recode multiple sense codons. This was demonstrated for Escherichia coli formate dehydrogenase and recombinant human thioredoxin reductase. In the picture the canonical genetic code table is overlaid with a single assay in which purple‐colored cells express active Sec‐containing enzymes.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201308584