Force-dependent fragility in RNA hairpins

Area of Science:

• Biophysics
• Chemical Physics

Background:

• Mechanical force can induce structural changes in biomolecules like RNA.
• Understanding the kinetics of unfolding and refolding is crucial for molecular dynamics.

Purpose of the Study:

• To investigate the dissociation of multiple bonds under mechanical force using Kramers theory.
• To interpret experimental results of RNA hairpin unfolding and refolding force distributions.
• To extend the validity of the two-state approximation for molecular force experiments.

Main Methods:

• Application of Kramers theory to analyze mechanical force-induced bond dissociation.
• Utilizing laser tweezers for single-molecule pulling experiments on RNA hairpins.
• Reconstruction of free-energy landscapes and identification of transition states.

Main Results:

• Identification of two distinct kinetic regimes in RNA hairpin unfolding/refolding.
• Interpretation of force distributions at different loading rates.
• Demonstration of a theoretical framework for analyzing molecular transitions.

Conclusions:

• The developed method provides a theoretical framework to reconstruct free-energy landscapes.
• It enables the identification of force-induced structural changes in molecular transition states.
• The approach is applicable to RNA hairpins with multiple kinetic barriers.