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Nat Commun. 2019 Jun 12;10(1):2579. doi: 10.1038/s41467-019-10608-z.

The structural basis for release-factor activation during translation termination revealed by time-resolved cryogenic electron microscopy.

Author information

1
Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA.
2
Department of Cell and Molecular Biology, Uppsala University, Uppsala, 751 24, Sweden.
3
Department of Biological Sciences, Barnard College, New York, NY, 10027, USA.
4
Department of Biological Sciences, Columbia University, New York, NY, 10027, USA.
5
Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA. jf2192@cumc.columbia.edu.
6
Department of Biological Sciences, Columbia University, New York, NY, 10027, USA. jf2192@cumc.columbia.edu.

Abstract

When the ribosome encounters a stop codon, it recruits a release factor (RF) to hydrolyze the ester bond between the peptide chain and tRNA. RFs have structural motifs that recognize stop codons in the decoding center and a GGQ motif for induction of hydrolysis in the peptidyl transfer center 70 Å away. Surprisingly, free RF2 is compact, with only 20 Å between its codon-reading and GGQ motifs. Cryo-EM showed that ribosome-bound RFs have extended structures, suggesting that RFs are compact when entering the ribosome and then extend their structures upon stop codon recognition. Here we use time-resolved cryo-EM to visualize transient compact forms of RF1 and RF2 at 3.5 and 4 Å resolution, respectively, in the codon-recognizing ribosome complex on the native pathway. About 25% of complexes have RFs in the compact state at 24 ms reaction time, and within 60 ms virtually all ribosome-bound RFs are transformed to their extended forms.

PMID:
31189921
PMCID:
PMC6561943
DOI:
10.1038/s41467-019-10608-z
[Indexed for MEDLINE]
Free PMC Article

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