Plant protein interactions studied using AFM force spectroscopy: nanomechanical and adhesion properties

Area of Science:

• Biophysics
• Materials Science
• Food Science

Background:

• Rapeseed (Brassica napus L.) proteins, napin (2S albumin) and cruciferin (12S globulin), are crucial seed components with distinct molecular weights.
• Understanding their nanomechanical and adhesion properties is essential for applications in food technology and biomaterials.

Purpose of the Study:

• To characterize the nanomechanical properties and adhesion forces of napin and cruciferin rapeseed proteins.
• To investigate the influence of protein type, pH, and tip-protein interactions on adhesion.
• To elucidate the role of residence time and electrostatic interactions in protein assembly at the nanoscale.

Main Methods:

• Atomic Force Microscopy (AFM) with chemically modified tips was employed for force spectroscopy.
• Single-molecule and multi-molecule force measurements were conducted under varying pH conditions.
• Analysis of protein unfolding length and force characteristics.

Main Results:

• Significant differences in tip-protein interaction strength were observed based on protein type and environmental pH.
• Protein-protein adhesion forces are strongly influenced by residence time and electrostatic interactions.
• Nanomechanical properties, including unfolding length and force, are sensitive to the structural characteristics of rapeseed proteins.

Conclusions:

• This study provides detailed insights into the nanoscale behavior of napin and cruciferin rapeseed proteins.
• The findings enhance the understanding of protein interactions and self-assembly mechanisms.
• Results contribute to the characterization of rapeseed proteins for potential applications.