EMD-2695
Cryo-EM map of Trigger Factor bound to a translating ribosome
EMD-2695
Single-particle7.7 Å
Deposition: 27/06/2014
Map released: 15/07/2015
Last modified: 28/09/2016
Sample Organism:
Escherichia coli
Sample: TnaC-stalled-RNC with Trigger factor
Fitted models: 4urd (Avg. Q-score: 0.042)
Deposition Authors: Deeng J, Chan KY, van der Sluis E, Bischoff L, Berninghausen O, Han W, Gumbart J, Schulten K , Beatrix B, Beckmann R
Sample: TnaC-stalled-RNC with Trigger factor
Fitted models: 4urd (Avg. Q-score: 0.042)
Deposition Authors: Deeng J, Chan KY, van der Sluis E, Bischoff L, Berninghausen O, Han W, Gumbart J, Schulten K , Beatrix B, Beckmann R
Dynamic Behavior of Trigger Factor on the ribosome
Deeng J,
Chan KY,
van der Sluis E,
Bischoff L,
Berninghausen O,
Han W,
Gumbart J,
Schulten K ,
Beatrix B,
Beckmann R
(2016) J. Mol. Biol. , 428 , 3588 - 3602
(2016) J. Mol. Biol. , 428 , 3588 - 3602
Abstract:
Trigger factor (TF) is the only ribosome-associated chaperone in bacteria. It interacts with hydrophobic segments in nascent chain (NCs) as they emerge from the ribosome. TF binds via its N-terminal ribosome-binding domain (RBD) mainly to ribosomal protein uL23 at the tunnel exit on the large ribosomal subunit. Whereas earlier structural data suggested that TF binds as a rigid molecule to the ribosome, recent comparisons of structural data on substrate-bound, ribosome-bound, and TF in solution from different species suggest that this chaperone is a rather flexible molecule. Here, we present two cryo-electron microscopy structures of TF bound to ribosomes translating an mRNA coding for a known TF substrate from Escherichia coli of a different length. The structures reveal distinct degrees of flexibility for the different TF domains, a conformational rearrangement of the RBD upon ribosome binding, and an increase in rigidity within TF when the NC is extended. Molecular dynamics simulations agree with these data and offer a molecular basis for these observations.
Trigger factor (TF) is the only ribosome-associated chaperone in bacteria. It interacts with hydrophobic segments in nascent chain (NCs) as they emerge from the ribosome. TF binds via its N-terminal ribosome-binding domain (RBD) mainly to ribosomal protein uL23 at the tunnel exit on the large ribosomal subunit. Whereas earlier structural data suggested that TF binds as a rigid molecule to the ribosome, recent comparisons of structural data on substrate-bound, ribosome-bound, and TF in solution from different species suggest that this chaperone is a rather flexible molecule. Here, we present two cryo-electron microscopy structures of TF bound to ribosomes translating an mRNA coding for a known TF substrate from Escherichia coli of a different length. The structures reveal distinct degrees of flexibility for the different TF domains, a conformational rearrangement of the RBD upon ribosome binding, and an increase in rigidity within TF when the NC is extended. Molecular dynamics simulations agree with these data and offer a molecular basis for these observations.