Detergent-Triggered Membrane Remodelling Monitored via Intramembrane Fluorescence Dequenching

Area of Science:

• Biochemistry
• Biophysics
• Membrane Biology

Background:

• Detergent-induced membrane solubilization is crucial for biotechnology, yet its mechanisms at the nanoscale remain unclear.
• Existing technologies struggle to assess nanoscopic membrane disruption events, leaving key questions about detergent remodeling and morphological transitions unanswered.

Purpose of the Study:

• To develop and utilize a sensitive, generalizable assay for probing nanoscale membrane remodeling induced by detergents.
• To elucidate the mechanistic details and morphological transitions leading to detergent-induced membrane solubilization.

Main Methods:

• Development of a single-color fluorescence dequenching assay using membrane-integrated fluorophores.
• Application of fluorescence spectroscopy, time-correlated single photon counting, single vesicle fluorescence lifetime imaging, and scanning electron microscopy.
• Investigation of Triton X-100's effects on membrane structure at sub-solubilizing concentrations.

Main Results:

• Triton X-100 induces substantial membrane morphological changes at concentrations below its critical micellar concentration.
• A transition from spherical vesicles to toroidal structures was observed during the swelling step, preceding solubilization.
• The fluorescence dequenching assay demonstrated robustness across different probes and conditions, confirming nanoscale sensitivity.

Conclusions:

• The study refines a multistep model of detergent-induced membrane solubilization.
• Fluorescence dequenching is established as a valuable tool for detecting conformational intermediates in membrane disruption.
• The assay platform can interrogate various molecular disruptors impacting membranes, with potential biomedical applications.