The effect of spin exchange interaction on protein structural stability

Area of Science:

• Biophysics
• Materials Science
• Protein Science

Background:

• Chiral molecules exhibit chiral induced spin selectivity (CISS), filtering electron spins based on handedness.
• CISS involves spin polarization and electric polarization in chiral molecules, previously studied with artificial molecules on magnetic surfaces.

Purpose of the Study:

• To investigate the role of intrinsic protein chirality in protein stability using magnetic nanoparticles.
• To explore how interactions with magnetic materials influence protein structural and functional resilience.

Main Methods:

• Proteins were adsorbed onto paramagnetic and ferromagnetic nanoparticles in solution.
• Protein unfolding was induced by gradual urea addition.
• Structural stability was assessed using bioluminescence (Luciferase activity) and fast spectroscopy (chromophore distance).

Main Results:

• Interactions with magnetic nanoparticles altered protein structural and functional resilience.
• Paramagnetic nanoparticles impeded minor structural disturbances at low urea concentrations.
• Ferromagnetic nanoparticles hindered major structural deformation at higher urea concentrations, attributed to spin exchange interactions.

Conclusions:

• Protein stability and integrity on magnetic surfaces are linked to internal spin exchange interactions.
• Chirality and spin exchange interactions are suggested as crucial factors in protein structure determination.
• Findings extend the understanding of CISS effects to biological molecules like proteins.