Regulation of catch binding by allosteric transitions.

Area of Science:

• Biophysics
• Molecular Biology
• Biochemistry

Background:

• Biological receptor-ligand bonds are crucial for cellular functions.
• External forces can significantly alter the stability and lifetime of these bonds.
• Previous models have not fully explained anomalous force-dependent bond lifetimes.

Purpose of the Study:

• To develop an allosteric model describing receptor-ligand bond lifetimes under external force.
• To explain the anomalous force and time dependencies of integrin-fibronectin bond lifetimes.
• To provide an analytic expression for bond lifetime as a function of force.

Main Methods:

• Utilized an allosteric model incorporating force-induced conformational changes.
• Applied the Bell mechanism to describe force effects on receptor-ligand interaction potentials.
• Derived an analytic expression for bond lifetime dependent on force and relaxation times.

Main Results:

• The model predicts that bond lifetime depends on the relaxation times of both the ligand and the allosteric site.
• An analytic expression for bond lifetime as a function of force was derived.
• The model accurately explains anomalous force and time dependencies in integrin-fibronectin bond lifetimes.

Conclusions:

• The developed allosteric model provides a robust framework for understanding force-dependent biological bond dynamics.
• The model successfully reconciles theoretical predictions with experimental observations of integrin-fibronectin bond behavior.
• This work offers insights into the mechanical regulation of molecular interactions in biological systems.