Tracking molecular interactions in membranes by simultaneous ATR-FTIR-AFM

Area of Science:

• Biophysics
• Spectroscopy
• Microscopy

Background:

• In situ atomic force microscopy (AFM) is crucial for real-time protein structure and assembly analysis at membrane interfaces.
• AFM conventionally struggles to confirm specific molecular conformations, especially during protein-membrane interactions, limiting functional insights.
• Subtle conformational changes critical to protein function upon membrane insertion are difficult to resolve with AFM alone.

Purpose of the Study:

• To develop an integrated platform combining in situ AFM with attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy.
• To overcome the limitations of AFM in directly measuring protein conformational changes at membrane interfaces.
• To simultaneously track conformational dynamics and topographical features for a comprehensive understanding of protein-membrane interactions.

Main Methods:

• Development of a novel platform integrating in situ atomic force microscopy (AFM).
• Coupling AFM with attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy.
• Simultaneous imaging and spectroscopic analysis of protein-membrane systems.

Main Results:

• Demonstrated the capability to track conformational changes not resolvable by in situ AFM.
• Provided topographical details not readily identifiable by conventional spectroscopy.
• Preliminary studies showed thermal transitions in supported lipid bilayers and lipid-induced conformational changes in adsorbed proteins.

Conclusions:

• The integrated AFM-ATR-FTIR platform offers a unique strategy for in situ functional imaging of protein-membrane interactions.
• This approach enables simultaneous tracking of molecular conformation and topographical features.
• The developed platform has significant potential for advancing the study of protein behavior at biological interfaces.