The pathway to GTPase activation of elongation factor SelB on the ribosome. Nature, 540(7631):80-85, 2016. cited By 38
The pathway to GTPase activation of elongation factor SelB on the ribosome [link]Paper  doi  abstract   bibtex   
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. © 2016 Macmillan Publishers Limited, part of Springer Nature.

Downloads: 0