Intradimer forces and their implication for conformations of von Willebrand factor multimers

Area of Science:

• Biophysics
• Computational Biology
• Hematology

Background:

• Von Willebrand factor (VWF) is a large glycoprotein crucial for hemostasis.
• VWF's mechanical and physicochemical properties are vital for arterial and microvascular clot formation.
• Recent findings indicate pH-dependent interactions within VWF dimeric subunits control its mechanical properties.

Purpose of the Study:

• To investigate the effect of intradimer forces on VWF multimer conformation under varying hydrodynamic conditions.
• To explore the role of VWF's subdimer dynamics in regulating hemostasis and thrombosis.

Main Methods:

• Development and parameterization of a coarse-grained computer model for VWF.
• Utilizing computer simulations to analyze VWF conformation under shear and non-shear stress.
• Comparing simulation data with experimental findings for model validation.

Main Results:

• Simulations revealed that strong attraction between VWF D4 domains enhances resistance to elongation under shear stress.
• Intermediate attraction between VWF C domains promotes VWF compaction in non-sheared fluid.
• The model demonstrated good agreement with experimental data.

Conclusions:

• Intradimer forces significantly influence VWF conformation in response to hydrodynamic conditions.
• Subdimer dynamics of VWF may act as a biophysical regulator of initial hemostasis.
• Understanding these dynamics is key to comprehending arterial thrombosis.