Related Experiment Videos
Effects of intermediate bound states in dynamic force spectroscopy
Imre Derényi1, Denis Bartolo, Armand Ajdari
1Department of Biological Physics, Eötvös University, H-1117 Budapest, Hungary. derenyi@elte.hu
Biophysical Journal
|March 3, 2004
Summary
Dynamic force spectroscopy experiments reveal complex energy landscapes. Our refined model shows multiple barriers can create more force-unbinding curve segments than previously thought, impacting barrier analysis.
Area of Science:
- Biophysics
- Physical Chemistry
- Materials Science
Background:
- Dynamic force spectroscopy (DFS) measures molecular unbinding forces.
- Standard theory links unbinding force (f*) to loading rate (r) via energy barriers.
- Current models predict linear segments in f* vs. log(r) plots, each corresponding to a barrier.
Purpose of the Study:
- To extend the theoretical interpretation of DFS experiments.
- To develop a more general analytical formula for multi-barrier systems.
- To investigate the impact of multiple energy barriers on experimental outcomes.
Main Methods:
- Application of a refined approximation to multi-barrier models.
- Derivation of a generalized analytical formula for unbinding force.
- Theoretical analysis of force-loading rate relationships.
Main Results:
- The refined model predicts up to N(N+1)/2 linear segments for N barriers, exceeding previous predictions.
- Multiple energy barriers can lead to ambiguity in determining barrier number and position.
- Multi-barrier landscapes can result in bimodal or multimodal unbinding force distributions.
Conclusions:
- The interpretation of DFS data requires careful consideration of potential multi-barrier landscapes.
- The number of observed linear segments does not directly equate to the number of energy barriers.
- Observed force distributions can provide insights into underlying energy landscapes.