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Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography
Published on: September 14, 2014
Visualization of the eEF2-80S ribosome transition-state complex by cryo-electron microscopy
Jayati Sengupta1, Jakob Nilsson, Richard Gursky
1Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA.
Journal of Molecular Biology
|July 23, 2008
Summary
Researchers visualized a key step in protein synthesis: the transition state of GTP hydrolysis by elongation factor 2 (eEF2) on the ribosome. This provides new insights into the ribosome-GTPase mechanism driving protein production.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Ribosome-mediated GTP hydrolysis by elongation factor 2 (eEF2) is crucial for protein synthesis.
- Understanding the transition state of this reaction is key to elucidating the translocation mechanism.
Purpose of the Study:
- To visualize the structural basis of ribosome-induced GTP hydrolysis on eEF2.
- To characterize the transition-state complex of eEF2 bound to the 80S ribosome.
Main Methods:
- Determined a 12.6-Å cryo-electron microscopy (cryo-EM) reconstruction.
- Utilized aluminum tetrafluoride (AlF4-) and GDP to mimic the transition state of GTP hydrolysis.
Main Results:
- First visualization of a ribosome-eEF2 transition-state complex.
- Identified tight interactions between eEF2's G domain and the large ribosomal subunit, and domain IV with an intersubunit bridge.
- Observed flexibility in eEF2 domains involved in small subunit binding.
- Found evidence for a transition-state conformation of the switch I region interacting with 40S subunit rRNA.
Conclusions:
- The determined structure provides a novel view of the eEF2-ribosome complex at the GTP hydrolysis transition state.
- Structural insights support a model for GTPase-coupled translocation.
- This distinct complex advances understanding of the molecular mechanisms governing protein synthesis.
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