Theoretical analysis of dynamic force spectroscopy experiments on ligand-receptor complexes

Area of Science:

• Biophysics
• Chemical Physics
• Molecular Biology

Background:

• Dynamic force spectroscopy (DFS) probes single molecular interactions.
• The rupture of chemical bonds in biomolecules is crucial for biological processes.
• A common assumption posits that bond rupture probability depends solely on instantaneous force.

Purpose of the Study:

• To investigate the validity of the force-dependent bond rupture assumption in biomolecular systems.
• To analyze experimental data from dynamic atomic force microscopy (AFM) force spectroscopy of a DNA-protein interaction.

Main Methods:

• Theoretical modeling of single chemical bond rupture under force.
• Experimental dynamic AFM force spectroscopy.
• Analysis of rupture force data for a specific ligand-receptor (DNA-protein) bond.

Main Results:

• A theoretical prediction of data collapse onto a master curve under the force-dependent assumption was made.
• Experimental DFS data for a DNA-protein bond did not exhibit this predicted data collapse.
• The findings indicate a deviation from the standard force-dependent rupture model.

Conclusions:

• The widely accepted assumption that bond rupture probability depends only on instantaneous force is not universally satisfied for biomolecular systems.
• Alternative explanations for the observed rupture behavior are discussed.
• This challenges current models of molecular unbinding dynamics.