Characterization of the L lambda phase in trehalose-stabilized dry membranes by solid-state NMR and X-ray diffraction

Area of Science:

• Biophysics
• Materials Science
• Structural Biology

Background:

• Lipid bilayers are essential for cell membrane structure and function.
• Anhydrobiosis requires cellular components, including membranes, to withstand extreme dehydration.
• Trehalose is a disaccharide known for its protective effects on biological structures during dehydration.

Purpose of the Study:

• To elucidate the mechanism by which trehalose (TRE) stabilizes lipid bilayers.
• To characterize the structural and dynamic changes in lipid bilayers upon trehalose interaction.
• To understand the role of trehalose in maintaining membrane viability under dry conditions.

Main Methods:

• Solid-state nuclear magnetic resonance (NMR) spectroscopy.
• X-ray powder diffraction.
• Calorimetry.

Main Results:

• Dry trehalose-stabilized lipid bilayers exhibit a first-order phase transition (L kappa to L lambda).
• X-ray diffraction reveals a lamellar structure with crystalline trehalose and disordered hydrocarbon chains in the L lambda phase.
• 2H and 13C NMR show extensive trehalose interaction with lipid headgroups and interfacial regions, hindering motion.

Conclusions:

• Trehalose stabilizes lipid bilayers by forming a hydrogen-bonded network with lipids, expanding inter-lipid distances.
• The L lambda phase, characterized by disordered acyl chains and stabilized headgroup regions, allows for membrane viability in anhydrobiosis.
• Trehalose acts as a molecular spacer and stabilizer, preserving membrane function in dehydrated states.