Biosynthesis of selenocysteine on its tRNA in eukaryotes.

Article Details

Citation

Copy to clipboard

Xu XM, Carlson BA, Mix H, Zhang Y, Saira K, Glass RS, Berry MJ, Gladyshev VN, Hatfield DL

Biosynthesis of selenocysteine on its tRNA in eukaryotes.

PLoS Biol. 2007 Jan;5(1):e4.

PubMed ID

17194211 [ View in PubMed

]

Abstract

Selenocysteine (Sec) is cotranslationally inserted into protein in response to UGA codons and is the 21st amino acid in the genetic code. However, the means by which Sec is synthesized in eukaryotes is not known. Herein, comparative genomics and experimental analyses revealed that the mammalian Sec synthase (SecS) is the previously identified pyridoxal phosphate-containing protein known as the soluble liver antigen. SecS required selenophosphate and O-phosphoseryl-tRNA([Ser]Sec) as substrates to generate selenocysteyl-tRNA([Ser]Sec). Moreover, it was found that Sec was synthesized on the tRNA scaffold from selenide, ATP, and serine using tRNA([Ser]Sec), seryl-tRNA synthetase, O-phosphoseryl-tRNA([Ser]Sec) kinase, selenophosphate synthetase, and SecS. By identifying the pathway of Sec biosynthesis in mammals, this study not only functionally characterized SecS but also assigned the function of the O-phosphoseryl-tRNA([Ser]Sec) kinase. In addition, we found that selenophosphate synthetase 2 could synthesize monoselenophosphate in vitro but selenophosphate synthetase 1 could not. Conservation of the overall pathway of Sec biosynthesis suggests that this pathway is also active in other eukaryotes and archaea that synthesize selenoproteins.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Pyridoxal phosphate	O-phosphoseryl-tRNA(Sec) selenium transferase	Protein	Humans	Unknown	Cofactor	Details