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Analyzing Protein Dynamics Using Hydrogen Exchange Mass Spectrometry
Published on: November 29, 2013
Apo-Hsp90 coexists in two open conformational states in solution
Patrick Bron1, Emmanuel Giudice, Jean-Paul Rolland
1UMR 6026 Université de Rennes 1-CNRS, Equipe SDM, Campus de Beaulieu, 35042 Rennes, France.
Biology of the Cell
|January 25, 2008
Summary
The 90 kDa heat-shock protein (Hsp90) exists in dynamic equilibrium between open states in solution, revealing its intrinsic flexibility drives conformational changes, not just nucleotide binding.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Heat-shock protein 90 (Hsp90) is crucial for client protein folding and activation.
- Hsp90 function involves nucleotide-dependent conformational changes.
- Previous structural data on Hsp90 conformational changes were limited to crystal states or prokaryotic homologs.
Purpose of the Study:
- To determine the nucleotide-free structure of the entire eukaryotic Hsp90.
- To investigate the intrinsic conformational flexibility of Hsp90 in solution.
- To re-evaluate the Hsp90 ATPase cycle based on new structural insights.
Main Methods:
- Small-angle X-ray scattering (SAXS).
- Single-particle cryo-electron microscopy (cryo-EM).
- Comparative structural analysis with HtpG and other Hsp90 structures.
Main Results:
- First nucleotide-free structures of full-length eukaryotic Hsp90 (apo-Hsp90) were obtained.
- Apo-Hsp90 exists in solution in a conformational equilibrium between two previously undescribed open states.
- Switching between apo-Hsp90 states involves large movements of the N-terminal domain (NTD) and middle domain (MD) around flexible hinges.
Conclusions:
- Eukaryotic apo-Hsp90 exhibits significant intrinsic flexibility in solution.
- Conformational rearrangements in Hsp90 are primarily driven by its inherent flexibility, rather than solely by nucleotide binding.
- The dynamic nature of Hsp90 is a key factor in its ATPase cycle.
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