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Investigating Receptor-ligand Systems of the Cellulosome with AFM-based Single-molecule Force Spectroscopy
Published on: December 20, 2013
Unbinding process of adsorbed proteins under external stress studied by atomic force microscopy spectroscopy
Summary
We studied how adsorbed fibrinogen proteins detach from silica surfaces under force. The rupture force increased with loading rate, and detachment forces were quantized in 180-200 pN steps.
Area of Science:
- Biophysics
- Surface Science
- Materials Science
Background:
- Adsorbed proteins on surfaces are crucial in biomaterials and biosensing.
- Understanding protein-surface interactions, especially unbinding dynamics, is key for controlling biological processes.
Purpose of the Study:
- To investigate the force-induced unbinding dynamics of adsorbed fibrinogen on hydrophilic silica.
- To analyze the relationship between loading rate and rupture force for protein detachment.
Main Methods:
- Utilized atomic force microscopy (AFM) spectroscopy to probe protein unbinding.
- Applied varying force loading rates (r(f)) to adsorbed fibrinogen on silica surfaces.
Main Results:
- Observed that the mean rupture force increases with the applied loading rate, similar to specific molecular interactions.
- Found that the dissociation rate at zero force is between 0.02 and 0.6 s⁻¹.
- Identified quantized rupture forces, appearing as integer multiples of 180-200 pN.
Conclusions:
- The Bell model effectively describes the unbinding dynamics of fibrinogen from silica under force.
- The quantized rupture forces suggest a discrete mechanism in the protein-surface unbinding process.
