Single molecular dynamic interactions between glycophorin A and lectin as probed by atomic force microscopy

Area of Science:

• Biophysics
• Molecular Biology
• Cellular Biology

Background:

• Glycophorin A (GpA) is a key transmembrane protein in human erythrocytes.
• GpA-lectin interactions serve as models for erythrocyte-related biological processes.

Purpose of the Study:

• To investigate the single molecular biophysical mechanisms of Glycophorin A-lectin interactions.
• To understand the force dynamics and energy landscape of GpA-lectin unbinding.

Main Methods:

• Utilized atomic force microscopy (AFM) in force mode for dynamic force spectroscopy.
• Probed GpA on mica surfaces and native erythrocyte membranes with Psathyrella velutina lectin (PVL)-coated AFM tips.
• Employed covalent crosslinkers for AFM tip functionalization.

Main Results:

• Identified a consistent unbinding force of approximately 60 pN for GpA-lectin interactions.
• Observed weak dependence of unbinding force on loading rate, indicating a single energy barrier.
• Force profile analysis revealed over 70% of GpA molecules lack cytoskeletal associations.

Conclusions:

• The unbinding of GpA from PVL is governed by a single energy barrier.
• GpA-lectin interactions exhibit consistent biophysical properties on both artificial and native erythrocyte surfaces.
• Findings contribute to understanding erythrocyte membrane protein dynamics and interactions.