A selenium-containing nucleoside at the first position of the anticodon in seleno-tRNAGlu from Clostridium sticklandii.

Abstract

The single selenonucleoside component of a Se-containing tRNAGlu isolated from C. sticklandii was 5-methyl-aminomethyl-2-selenouridine. This selenonucleoside is most likely located at the wobble position of the anticodon of the clostridial seleno-tRNAGlu. Nuclease T1 digestion of this seleno-tRNAGlu generated one major Se-containing oligonucleotide (25 bases long). The Se-contianing residue within this oligonucleotide was located by sequence analysis of the oligonucleotide before and after removal of Se by treatment with cyanogen bromide. The sequence of this oligonucleotide, A-A-C-C-G-C-C-C-U-U+-U-C-A+-C-G-G-C-G-G-U-A-A-C-A-G, is homologous to that of the Escherichia coli .**GRAPHIC**. from residues 27-50, including the anticodon region and the variable loop, except that the E. coli tRNA has 5-methylaminomethyl-2-thiouridine instead of the selenonucleoside.