Structural highlights
Function[PSTK_METJA] Specifically phosphorylates seryl-tRNA(Sec) to O-phosphoseryl-tRNA(Sec), an activated intermediate for selenocysteine biosynthesis. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 21(st) amino acid, selenocysteine (Sec), is assigned to the codon UGA and is biosynthesized on the selenocysteine-specific tRNA (tRNA(Sec)) with the corresponding anticodon. In archaea/eukarya, tRNA(Sec) is ligated with serine by seryl-tRNA synthetase (SerRS), the seryl moiety is phosphorylated by O-phosphoseryl-tRNA kinase (PSTK), and the phosphate group is replaced with selenol by Sep-tRNA:Sec-tRNA synthase. PSTK selectively phosphorylates seryl-tRNA(Sec), while SerRS serylates both tRNA(Ser) and tRNA(Sec). In this study, we determined the crystal structures of the archaeal tRNA(Sec).PSTK complex. PSTK consists of two independent linker-connected domains, the N-terminal catalytic domain (NTD) and the C-terminal domain (CTD). The D-arm.CTD binding occurs independently of and much more strongly than the acceptor-arm.NTD binding. PSTK thereby distinguishes the characteristic D arm with the maximal stem and the minimal loop of tRNA(Sec) from the canonical D arm of tRNA(Ser), without interacting with the anticodon. This mechanism is essential for the UGA-specific encoding of selenocysteine. Structural basis for the major role of O-phosphoseryl-tRNA kinase in the UGA-specific encoding of selenocysteine.,Chiba S, Itoh Y, Sekine S, Yokoyama S Mol Cell. 2010 Aug 13;39(3):410-20. PMID:20705242[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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