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Force-extension behavior of folding polymers
S Cocco1, J F Marko, R Monasson
1LDFC CNRS-ULP, Institut de Physique, 3 rue de l'Université, 67084 Strasbourg, France.
The European Physical Journal. E, Soft Matter
|March 12, 2004
Summary
Flexible polymers with folded or unfolded elements exhibit enhanced elasticity, mimicking linear behavior with increased force scales. This phenomenon is observed in biopolymers like DNA and chromatin fibers.
Area of Science:
- Polymer Physics
- Biophysics
- Materials Science
Background:
- Flexible polymers, particularly biopolymers, often feature elements that can switch between folded and unfolded states.
- These conformational changes, driven by intrinsic interactions or molecular binding, significantly influence polymer elasticity.
Purpose of the Study:
- To investigate the elastic response of flexible polymers with switchable elements.
- To analyze how folding interactions affect polymer elasticity, especially when comparable to thermal energy (kBT).
- To connect theoretical models with experimental observations in biopolymers.
Main Methods:
- Utilizing simple flexible-chain polymer models.
- Analyzing theoretical elastic response under varying energy conditions.
- Comparing model predictions with experimental data from DNA and chromatin fibers.
Main Results:
- Demonstrated that polymer elasticity can mimic linear elasticity with an enhanced force scale.
- Showed this effect persists even when folding energy is comparable to kBT.
- Observed this phenomenon in single-stranded DNA, chromatin fiber, and protein-bound double-stranded DNA.
Conclusions:
- The folding of polymer elements significantly enhances elastic response beyond backbone flexibility.
- Theoretical models accurately predict experimental observations in various biopolymer systems.
- Understanding these elastic properties is crucial for biopolymers with complex interactions.