Biosynthesis of selenium-modified tRNAs in Methanococcus vannielii

Michael Politino, Lin Tsai, Zsuzsa Veres, Thressa C. Stadtman

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Selenium-containing nucleosides are natural components of several tRNA species in Methanococcus vannielii. In the present study, the incorporation of selenium from 75SeO32- into these macromolecules was investigated in sonic extracts of M. vannielii. Nucleoside analysis of the 75Se-labeled tRNAs from these in vitro reaction mixtures demonstrated that the selenium was present in 75Se-labeled nucleosides identical to the two naturally occurring 2-selenouridines produced in vivo. Incorporation of selenium into these nucleosides was ATP-dependent and was maximal after 20 min. Addition of O-acetylserine enhanced the activity 2- to 3-fold, implicating a role for selenocysteine in the reaction. Added L-selenocysteine could function as a selenium donor, but the D isomer and DL-selenomethionine were inactive. RPC-5 chromatography of bulk tRNA isolated from M. vannielii grown on 75SeO32- separated five major species of seleno-tRNAs. The amino acid-accepting activity of these tRNAs was investigated.

Original languageEnglish
Pages (from-to)6345-6348
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number16
Publication statusPublished - Aug 1990



  • Aminoacylation
  • Seleno-tRNAs

ASJC Scopus subject areas

  • General

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