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Piecing Together the Allosteric Patterns of Chaperonin GroEL
Jin Chen1, Qian Zhang2, Weitong Ren3
1Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences , Okazaki 444-8787, Japan.
The Journal of Physical Chemistry. B
|April 22, 2017
Summary
This study develops a new method to understand the complex allosteric mechanisms of the large chaperonin GroEL in solution. The findings provide a detailed molecular map of GroEL
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Biophysics
Background:
- Elucidating allostery in large macromolecular assemblies in solution is challenging due to structural complexity.
- Chaperonin GroEL, an ~800 kDa tetradecamer from E. coli, plays a crucial role in protein folding.
- Understanding GroEL allostery is key to comprehending its function in cellular protein homeostasis.
Purpose of the Study:
- To develop and apply a novel methodology for characterizing the allosteric patterns of chaperonin GroEL in solution.
- To quantitatively map allosteric changes in GroEL at a molecular level.
- To identify key residues and dynamics governing GroEL allosteric transitions.
Main Methods:
- Combined amide backbone hydrogen/deuterium exchange with mass spectrometry (HDX-MS).
- Utilized fluorescence spectroscopy and molecular simulations (coarse-grained molecular dynamics).
- Analyzed 133 overlapping proteolytic peptides for >95% sequence coverage of GroEL.
Main Results:
- Quantitatively mapped GroEL allosteric changes in solution with residue-level resolution.
- Identified specific residues critical for GroEL allosteric determinants.
- Monitored localized dynamics using tryptophan-mutated GroEL and evaluated conformational transitions via simulations.
Conclusions:
- A practical and comprehensive methodology was established for analyzing GroEL allostery in solution.
- The study provides refined insights into the molecular mechanisms of GroEL allosteric regulation.
- This approach can be extended to study allostery in other large macromolecular systems.