The pathway to GTPase activation of elongation factor SelB on the ribosome
2016 | journal article; research paper. A publication with affiliation to the University of Göttingen.
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- Authors
- Fischer, Niels ; Neumann, Piotr ; Bock, Lars V. ; Maracci, Cristina ; Wang, Zhe; Paleskava, Alena ; Konevega, Andrey L. ; Schröder, Gunnar F.; Grubmüller, Helmut ; Ficner, Ralf ; Rodnina, Marina V. ; Stark, Holger
- Abstract
- In all domains of life, selenocysteine (Sec) is delivered to the ribosome by selenocysteine-specific tRNA (tRNA(Sec)) with the help of a specialized translation factor, SelB in bacteria. Sec-tRNA(Sec) 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(Sec) binding by SelB and show large-scale rearrangements of Sec-tRNA(Sec). Upon initial binding of SelB-Sec-tRNA(Sec) to the ribosome and codon reading, the 30S subunit adopts an open conformation with Sec-tRNA(Sec) 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(Sec) 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.
- Issue Date
- 2016
- Journal
- Nature
- ISSN
- 0028-0836
- eISSN
- 1476-4687
- Language
- English