Phenomenological and microscopic theories for catch bonds.

Area of Science:

• Biophysics
• Molecular Biology
• Biochemistry

Background:

• Protein complexes typically weaken under mechanical force.
• Catch bonding describes non-covalent bonds strengthening with applied force, a counter-intuitive phenomenon.
• Understanding catch bonds is crucial for various biological systems.

Purpose of the Study:

• To assess the successes and limitations of existing theories explaining catch-bond behavior.
• To evaluate phenomenological and microscopic theories against experimental data.
• To investigate the physical relevance of parameters in catch-bond models.

Main Methods:

• Analysis of phenomenological two-state models.
• Evaluation of experimental data from various biological complexes (actomyosin, kinetochore-microtubule, selectin-ligand, cadherin-catenin).
• Description of a microscopic theory for selectins.

Main Results:

• A phenomenological two-state model successfully fits diverse experimental data.
• A microscopic theory for selectins provides a structural basis for catch bonds.
• The theory predicts a key allosteric role for Asn82-Glu88 residues in selectins.

Conclusions:

• Phenomenological models are widely applicable but require evaluation of physical parameter relevance.
• Microscopic theories offer structural insights into catch-bond mechanisms.
• Further development of theories and simulations is needed to mimic complex experimental conditions and biological contexts.