EMD-1665
Alpha-helical nascent polypeptide chains visualized within distinct regions of the ribosomal exit tunnel
EMD-1665
Single-particle7.3 Å
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Map released: 05/02/2010
Last modified: 24/10/2012
Sample Organism:
Triticum sp.
Sample: This map represents a wheat germ 80S ribosomal nascent chain complex with a helical nascent chain
Deposition Authors: Bhushan S
,
Gartmann M,
Halic M,
Armache JP
,
Jarasch A,
Mielke T,
Berninghausen O,
Wilson DN
,
Beckmann R
Sample: This map represents a wheat germ 80S ribosomal nascent chain complex with a helical nascent chain
Deposition Authors: Bhushan S
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alpha-Helical nascent polypeptide chains visualized within distinct regions of the ribosomal exit tunnel.
Bhushan S
,
Gartmann M,
Halic M,
Armache JP
,
Jarasch A,
Mielke T,
Berninghausen O,
Wilson DN
,
Beckmann R
(2010) Nat. Struct. Mol. Biol. , 17 , 313 - 317
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(2010) Nat. Struct. Mol. Biol. , 17 , 313 - 317
Abstract:
As translation proceeds, the nascent polypeptide chain passes through a tunnel in the large ribosomal subunit. Although this ribosomal exit tunnel was once thought only to be a passive conduit for the growing nascent chain, accumulating evidence suggests that it may in fact play a more active role in regulating translation and initial protein folding events. Here we have determined single-particle cryo-electron microscopy reconstructions of eukaryotic 80S ribosomes containing nascent chains with high alpha-helical propensity located within the exit tunnel. The maps enable direct visualization of density for helices as well as allowing the sites of interaction with the tunnel wall components to be elucidated. In particular regions of the tunnel, the nascent chain adopts distinct conformations and establishes specific contacts with tunnel components, both ribosomal RNA and proteins, that have been previously implicated in nascent chain-ribosome interaction.
As translation proceeds, the nascent polypeptide chain passes through a tunnel in the large ribosomal subunit. Although this ribosomal exit tunnel was once thought only to be a passive conduit for the growing nascent chain, accumulating evidence suggests that it may in fact play a more active role in regulating translation and initial protein folding events. Here we have determined single-particle cryo-electron microscopy reconstructions of eukaryotic 80S ribosomes containing nascent chains with high alpha-helical propensity located within the exit tunnel. The maps enable direct visualization of density for helices as well as allowing the sites of interaction with the tunnel wall components to be elucidated. In particular regions of the tunnel, the nascent chain adopts distinct conformations and establishes specific contacts with tunnel components, both ribosomal RNA and proteins, that have been previously implicated in nascent chain-ribosome interaction.