Joanne M. L. Ho

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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(More)
Selenocysteine (Sec) biosynthesis in archaea and eukaryotes requires three steps: serylation of tRNA(Sec) by seryl-tRNA synthetase (SerRS), phosphorylation of Ser-tRNA(Sec) by O-phosphoseryl-tRNA(Sec) kinase (PSTK), and conversion of O-phosphoseryl-tRNA(Sec) (Sep-tRNA(Sec)) by Sep-tRNA:Sec-tRNA synthase (SepSecS) to Sec-tRNA(Sec). Although SerRS recognizes(More)
O-Phosphoseryl-tRNA kinase (PSTK) is the key enzyme in recruiting selenocysteine (Sec) to the genetic code of archaea and eukaryotes. The enzyme phosphorylates Ser-tRNA(Sec) to produce O-phosphoseryl-tRNA(Sec) (Sep-tRNA(Sec)) that is then converted to Sec-tRNA(Sec) by Sep-tRNA:Sec-tRNA synthase. Earlier we reported the structure of the Methanocaldococcus(More)
Expansion of the genetic code through engineering the translation machinery has greatly increased the chemical repertoire of the proteome. This has been accomplished mainly by read-through of UAG or UGA stop codons by the noncanonical aminoacyl-tRNA of choice. While stop codon read-through involves competition with the translation release factors, sense(More)
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