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B6db activities:
Description L-seryl-tRNA(Sec) selenium transferase
Alternative names Selenocysteine synthase.
L-selenocysteinyl-tRNA(Sel) synthase;
L-selenocysteinyl-tRNA(Sec) synthase;
Cysteinyl-tRNA(Sel)-selenium transferase;
Cysteinyl-tRNA(Sec)-selenium transferase.
Catalyzed reaction L-seryl-tRNA(Sec) + selenophosphate = L-selenocysteinyl-tRNA(Sec) + H(2)O + phosphate.
Cofactor Pyridoxal-phosphate.
Comments -!- Recognizes specifically tRNA(Sec)-species. Binding of tRNA(Sec) also occurs in the absence of the seryl group.
-!- 2-Aminoacryloyl-tRNA, bound to the enzyme as an imine with the pyridoxal phosphate, is an intermediate in the reaction.
-!- Since the selenium atom replaces oxygen in serine, the product may also be referred to as L-selenoseryl-tRNA(Sel).
-!- The abbreviation Sel has also been used for selenocysteine but Sec is preferred.
This specific activity occurs apparently only in bacteria; in archaea and eukaryotes, the L-selenocysteinyl-tRNA species is synthesized from O-phosphoseryl-tRNA(Ser) by Sec synthase (L-phosphoseryl-tRNA(Ser):selenophosphate seleniumtransferase).
PDB 3W1J; 3W1I; 3W1H;
Organisms -Eubacteria

Family (28)
Links Enzyme (activities)
BRENDA (activities)
KEGG (pathways)
PLPMDB (PLP mutants)
  Itoh Y1, Bröcker MJ, Sekine S, Hammond G, Suetsugu S, Söll D, Yokoyama S. (2013) Decameric SelA•tRNA(Sec) ring structure reveals mechanism of bacterial selenocysteine formation. Science. 340 75-8.

 Gursinsky, T.; Jager, J.; Andreesen, J. R.; Sohling, B. (2000) A selDABC cluster for selenocysteine incorporation in Eubacterium acidaminophilum Arch Microbiol 174 200-12.

 Tormay, P.; Wilting, R.; Lottspeich, F.; Mehta, P. K.; Christen, P.; Bock, A. (1998) Bacterial selenocysteine synthase--structural and functional properties Eur J Biochem 254 655-61.

 Forchhammer, K.; Leinfelder, W.; Boesmiller, K.; Veprek, B.; Bock, A. (1991) Selenocysteine synthase from Escherichia coli. Nucleotide sequence of the gene (selA) and purification of the protein J Biol Chem 266 6318-23.

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last changed 2019/06/20 11:47

B6db activities