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Title | The pathway to GTPase activation of elongation factor SelB on the ribosome. |
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Journal, issue, pages | Nature, Vol. 540, Issue 7631, Page 80-85, Year 2016 |
Publish date | Dec 1, 2016 |
Authors | Niels Fischer / Piotr Neumann / Lars V Bock / Cristina Maracci / Zhe Wang / Alena Paleskava / Andrey L Konevega / Gunnar F Schröder / Helmut Grubmüller / Ralf Ficner / Marina V Rodnina / Holger Stark / |
PubMed Abstract | In all domains of life, selenocysteine (Sec) is delivered to the ribosome by selenocysteine-specific tRNA (tRNA) with the help of a specialized translation factor, SelB in bacteria. Sec-tRNA recodes ...In all domains of life, selenocysteine (Sec) is delivered to the ribosome by selenocysteine-specific tRNA (tRNA) with the help of a specialized translation factor, SelB in bacteria. Sec-tRNA recodes a UGA stop codon next to a downstream mRNA stem-loop. Here we present the structures of six intermediates on the pathway of UGA recoding in Escherichia coli by single-particle cryo-electron microscopy. The structures explain the specificity of Sec-tRNA binding by SelB and show large-scale rearrangements of Sec-tRNA. Upon initial binding of SelB-Sec-tRNA to the ribosome and codon reading, the 30S subunit adopts an open conformation with Sec-tRNA covering the sarcin-ricin loop (SRL) on the 50S subunit. Subsequent codon recognition results in a local closure of the decoding site, which moves Sec-tRNA away from the SRL and triggers a global closure of the 30S subunit shoulder domain. As a consequence, SelB docks on the SRL, activating the GTPase of SelB. These results reveal how codon recognition triggers GTPase activation in translational GTPases. |
External links | Nature / PubMed:27842381 |
Methods | EM (single particle) |
Resolution | 3.4 - 5.3 Å |
Structure data | EMDB-4121, PDB-5lza: EMDB-4122, PDB-5lzb: EMDB-4123, PDB-5lzc: EMDB-4124, PDB-5lzd: |
Chemicals | ChemComp-ZN: ChemComp-FME: ChemComp-SEC: ChemComp-GNP: ChemComp-MG: ChemComp-HOH: ChemComp-CL: |
Source |
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Keywords | RIBOSOME / translation / decoding / recoding / selenocysteine |