Interaction of translation factor SELB with the formate dehydrogenase H selenopolypeptide mRNA.
The SELB protein from Escherichia coli is a specialized elongation factor required for the UGA-directed insertion of the amino acid selenocysteine into selenopolypeptides. Discrimination of the UGA codon requires the presence of a recognition element within the mRNA, which is located at the 3' side of the UGA codon; a hairpin structure can be formed within this mRNA region. By gel shift assays, a specific interaction between SELB and the mRNA recognition element could be demonstrated. Footprinting experiments, using nucleases or iodine as cleaving agents, showed that SELB binds to the loop region of the hairpin structure. In the presence of selenocysteinyl-tRNA, SELB formed a complex with the charged tRNA and the mRNA. The results indicate that targeted insertion of selenocysteine is accomplished by the binding of the SELB protein to this mRNA recognition element, resulting in the formation of a selenocysteinyl-tRNA.SELB complex at the mRNA in the immediate neighborhood of the UGA codon.
Baron
C
C
Lehrstuhl für Mikrobiologie, Universität München, Germany.
Heider
J
J
Böck
A
A
D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005560:Formate Dehydrogenases / Q000235:genetics*; D005798:Genes, Bacterial; D006864:Hydrogenase / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics*; D009690:Nucleic Acid Conformation; D010445:Peptide Elongation Factors / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D051140:Selenoproteins; D013379:Substrate Specificity; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D009097:Multienzyme Complexes; D010445:Peptide Elongation Factors; D011506:Proteins; D012333:RNA, Messenger; D012346:RNA, Transfer, Amino Acyl; C061878:SelB protein, Bacteria; D051140:Selenoproteins; C112705:selenocysteinyl-tRNA; D006864:Hydrogenase; D005560:Formate Dehydrogenases; C054017:formate hydrogenlyase