Testing Landscape Theory for Biomolecular Processes with Single Molecule Fluorescence Spectroscopy.

Area of Science:

• Biophysics
• Physical Chemistry
• Molecular Dynamics

Background:

• Kramers' theory is crucial for understanding biomolecular processes.
• Experimental validation of this theory in complex systems is lacking.
• The 1D free energy profile model is a simplification of real-world dynamics.

Purpose of the Study:

• To experimentally test Kramers' theory for diffusive barrier crossing.
• To validate the 1D diffusion scenario using a model biomolecular system.
• To determine the transition path time for DNA hairpin folding.

Main Methods:

• Single-molecule fluorescence measurements were employed.
• DNA hairpin folding dynamics were analyzed.
• Optical tweezer measurements provided theoretical parameters.

Main Results:

• The 1D diffusion scenario was successfully tested.
• An upper bound of 2.5 microseconds was found for the average transition path time.
• Experimental results were consistent with theoretical predictions.

Conclusions:

• The study provides the first rigorous experimental test of Kramers' theory in a 1D diffusion scenario.
• Findings support the applicability of Kramers' theory to biomolecular processes.
• The determined transition path time offers insights into DNA hairpin folding dynamics.