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Facile Recoding of Selenocysteine in Nature
Author(s) -
Mukai Takahito,
Englert Markus,
Tripp H. James,
Miller Corwin,
Ivanova Natalia N.,
Rubin Edward M.,
Kyrpides Nikos C.,
Söll Dieter
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201511657
Subject(s) - selenocysteine , genetic code , transfer rna , stop codon , selenoprotein , biology , genetics , computational biology , genome , codon usage bias , formate dehydrogenase , rna , gene , biochemistry , enzyme , cofactor , glutathione , glutathione peroxidase , cysteine
Selenocysteine (Sec or U) is encoded by UGA, a stop codon reassigned by a Sec‐specific elongation factor and a distinctive RNA structure. To discover possible code variations in extant organisms we analyzed 6.4 trillion base pairs of metagenomic sequences and 24 903 microbial genomes for tRNA Sec species. As expected, UGA is the predominant Sec codon in use. We also found tRNA Sec species that recognize the stop codons UAG and UAA, and ten sense codons. Selenoprotein synthesis programmed by UAG in Geodermatophilus and Blastococcus, and by the Cys codon UGU in Aeromonas salmonicida was confirmed by metabolic labeling with 75 Se or mass spectrometry. Other tRNA Sec species with different anticodons enabled E. coli to synthesize active formate dehydrogenase H, a selenoenzyme. This illustrates the ease by which the genetic code may evolve new coding schemes, possibly aiding organisms to adapt to changing environments, and show the genetic code is much more flexible than previously thought.