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Key Intermediates in Ribosome Recycling Visualized by Time-Resolved Cryoelectron Microscopy
Ziao Fu1, Sandip Kaledhonkar2, Anneli Borg3
1Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
Structure (London, England : 1993)
|November 8, 2016
Summary
Ribosome recycling separates ribosomal subunits after protein synthesis termination. Time-resolved cryo-electron microscopy visualized key intermediate complexes, revealing insights into this essential cellular process.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Polypeptide synthesis terminates at stop codons via release factors.
- The post-termination complex (PostTC) remains bound to mRNA and deacylated tRNA.
- Ribosome recycling separates subunits for subsequent translation initiation.
Purpose of the Study:
- To visualize transient intermediate structures during ribosome recycling.
- To elucidate the mechanism of ribosome recycling promoted by RRF and EF-G.
- To demonstrate the utility of time-resolved cryo-EM for studying dynamic molecular processes.
Main Methods:
- Time-resolved cryo-electron microscopy (cryo-EM) using a mixing-spraying technique.
- Visualization of short-lived intermediate complexes during ribosome recycling.
- Analysis of native forms of RRF/EF-G-bound PostTC and deacylated tRNA-bound 30S subunits.
Main Results:
- Identified and visualized two key intermediate complexes in ribosome recycling.
- Observed complexes containing both ribosome recycling factor (RRF) and elongation factor G (EF-G) bound to the PostTC.
- Captured structures of deacylated tRNA bound to the 30S ribosomal subunit during recycling.
Conclusions:
- Time-resolved cryo-EM is a powerful technique for visualizing transient molecular structures.
- The study provides structural insights into the mechanism of ribosome recycling.
- Understanding ribosome recycling is crucial for regulating protein synthesis.
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