EMD-20204
RF2 accommodated state bound 70S complex at long incubation time
EMD-20204
Single-particle3.7 Å
Deposition: 05/05/2019
Map released: 19/06/2019
Last modified: 20/03/2024
Sample Organism:
Escherichia coli
Sample: Release complex 70S ribosomes
Fitted models: 6ouo (Avg. Q-score: 0.247)
Deposition Authors: Fu Z , Indrisiunaite G
Sample: Release complex 70S ribosomes
Fitted models: 6ouo (Avg. Q-score: 0.247)
Deposition Authors: Fu Z , Indrisiunaite G
The structural basis for release-factor activation during translation termination revealed by time-resolved cryogenic electron microscopy.
Fu Z ,
Indrisiunaite G ,
Kaledhonkar S,
Shah B ,
Sun M ,
Chen B,
Grassucci RA,
Ehrenberg M,
Frank J
(2019) Nat Commun , 10 , 2579 - 2579
(2019) Nat Commun , 10 , 2579 - 2579
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.
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.