Tethered bilayer membranes as a complementary tool for functional and structural studies: The pyolysin case.

Area of Science:

• Biophysics
• Biochemistry
• Membrane protein studies

Background:

• Cholesterol-dependent cytolysins (CDCs) are pore-forming toxins impacting cell membranes.
• Understanding CDC mechanisms is crucial for developing therapeutic interventions.
• Tethered bilayer lipid membranes (tBLMs) offer a platform for studying membrane-protein interactions.

Purpose of the Study:

• To utilize tBLMs and electrochemical impedance spectroscopy (EIS) for real-time analysis of CDC activity.
• To investigate the structural and functional effects of pyolysin (PLO) on lipid bilayers.
• To assess the efficacy of potential inhibitors against CDC-mediated membrane damage.

Main Methods:

• Real-time monitoring of tBLMs using electrochemical impedance spectroscopy (EIS).
• Reconstitution of pyolysin (PLO) and its mutant into tBLMs.
• Complementary structural analysis using atomic force microscopy (AFM) and neutron reflectometry (NR).

Main Results:

• EIS detected membrane damage consistent with pore formation by PLO.
• A non-pore-forming PLO mutant did not alter EIS parameters, validating the method.
• AFM and NR provided structural insights into membrane-bound PLO.
• Dynasore demonstrated a protective effect against PLO and pneumolysin in tBLMs.

Conclusions:

• tBLMs coupled with EIS provide a reliable platform for studying CDC activity.
• This method can quantify membrane damage induced by pore-forming toxins.
• tBLMs serve as a valuable model for developing strategies against CDC toxicity.