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Covalent Immobilization of Proteins for the Single Molecule Force Spectroscopy
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Probing Activated and Non-Activated Single Calmodulin Molecules under a Piconewton Compressive Force
1Center for Photochemical Sciences, Department of Chemistry , Bowling Green State University , Bowling Green , Ohio 43403 , United States.
Biochemistry
|March 9, 2018
Summary
Researchers applied piconewton compressive force to Calmodulin (CaM) using atomic force microscopy. Apo-CaM unexpectedly ruptured under compression, revealing a novel mechanical response important for protein interactions.
Area of Science:
- Biophysics
- Molecular Biology
- Biochemistry
Background:
- Protein structure-function relationships are crucial for biological processes.
- Force manipulation studies, particularly pulling forces, have elucidated protein mechanics.
- Compressive force effects on protein structure remain largely unexplored.
Purpose of the Study:
- To investigate protein conformational changes under piconewton compressive force.
- To characterize the mechanical response of Calmodulin (CaM) under compression.
- To compare the behavior of Ca2+-ligated CaM and apo-CaM under compressive force.
Main Methods:
- Utilized a highly sensitive, high signal-to-noise atomic force microscopy (AFM) approach.
- Applied precise piconewton compressive forces to individual Calmodulin molecules.
- Manipulated both Ca2+-ligated activated CaM and Ca2+-free apo-CaM.
Main Results:
- Observed sudden and spontaneous structural rupture of apo-CaM under compressive force.
- No rupture events were observed for the Ca2+-ligated activated CaM form.
- This represents the first report of spontaneous structural rupture under piconewton compressive force.
Conclusions:
- Apo-CaM exhibits a unique mechanical instability under compressive force.
- This compressive force-induced rupture may play a role in protein-protein interactions.
- Findings suggest novel functions for protein mechanics in cellular signaling pathways.
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