Fibronectin module FN(III)9 adsorption at contrasting solid model surfaces studied by atomistic molecular dynamics

Area of Science:

• Biophysics
• Materials Science
• Computational Chemistry

Background:

• Fibronectin is crucial for cell adhesion and signaling.
• Understanding protein adsorption is key for biomaterials and biosensors.
• The FN(III)9 domain mediates integrin binding.

Purpose of the Study:

• Investigate the adsorption mechanism of the human fibronectin FN(III)9 domain.
• Analyze adsorption onto diverse model surfaces (mica, silica, Au {111}) at pH 7.
• Determine the influence of surface charge and electric fields on protein-surface interactions.

Main Methods:

• Atomistic molecular dynamics simulations.
• Utilized ionic models for mica and silica surfaces.
• Employed a non-polar model for Au {111}.

Main Results:

• Electrostatic interactions dominate rapid adsorption on silica surfaces with electric fields.
• FN(III)9 adsorbs to negatively charged mica due to the lack of a repulsive electric field.
• Protein dipole moment influences orientation; anchoring residues have opposite charges to the surface.
• Adsorption on Au {111} is less specific, involving various protein regions.

Conclusions:

• Adsorption mechanisms vary significantly across different model surfaces.
• Surface properties, particularly electrostatics, control FN(III)9 adsorption and orientation.
• Adsorption does not necessitate major conformational changes, suggesting preserved biological activity.