EMD-1922
Ribosome Assembly Factors Prevent Premature Translation Initiation by 40S Assembly Intermediates
EMD-1922
Single-particle30.0 Å
Deposition: 04/07/2011Map released: 04/11/2011
Last modified: 01/10/2014
Sample Organism:
Saccharomyces cerevisiae
Sample: Recombinant Tsr1
Deposition Authors: Strunk BS
,
Loucks CR,
Su M,
Vashisth H,
Cheng S ,
Schilling J,
BrooksIII CL,
Karbstein K ,
Skiniotis G
Sample: Recombinant Tsr1
Deposition Authors: Strunk BS
,
Loucks CR,
Su M,
Vashisth H,
Cheng S ,
Schilling J,
BrooksIII CL,
Karbstein K ,
Skiniotis G
Ribosome assembly factors prevent premature translation initiation by 40S assembly intermediates.
Strunk BS ,
Loucks CR,
Su M,
Vashisth H,
Cheng S ,
Schilling J,
Brooks CL,
Karbstein K ,
Skiniotis G
(2011) Science , 333 , 1449 - 1453
,
Loucks CR,
Su M,
Vashisth H,
Cheng S ,
Schilling J,
Brooks CL,
Karbstein K ,
Skiniotis G
(2011) Science , 333 , 1449 - 1453
Abstract:
Ribosome assembly in eukaryotes requires approximately 200 essential assembly factors (AFs) and occurs through ordered events that initiate in the nucleolus and culminate in the cytoplasm. Here, we present the electron cryo-microscopy (cryo-EM) structure of a late cytoplasmic 40S ribosome assembly intermediate from Saccharomyces cerevisiae at 18 angstrom resolution. We obtained cryo-EM reconstructions of preribosomal complexes lacking individual components to define the positions of all seven AFs bound to this intermediate. These late-binding AFs are positioned to prevent each step in the translation initiation pathway. Together, they obstruct the binding sites for initiation factors, prevent the opening of the messenger RNA channel, block 60S subunit joining, and disrupt the decoding site. These redundant mechanisms probably ensure that pre-40S particles do not enter the translation pathway, which would result in their rapid degradation.
Ribosome assembly in eukaryotes requires approximately 200 essential assembly factors (AFs) and occurs through ordered events that initiate in the nucleolus and culminate in the cytoplasm. Here, we present the electron cryo-microscopy (cryo-EM) structure of a late cytoplasmic 40S ribosome assembly intermediate from Saccharomyces cerevisiae at 18 angstrom resolution. We obtained cryo-EM reconstructions of preribosomal complexes lacking individual components to define the positions of all seven AFs bound to this intermediate. These late-binding AFs are positioned to prevent each step in the translation initiation pathway. Together, they obstruct the binding sites for initiation factors, prevent the opening of the messenger RNA channel, block 60S subunit joining, and disrupt the decoding site. These redundant mechanisms probably ensure that pre-40S particles do not enter the translation pathway, which would result in their rapid degradation.