Magnetically Alignable Bicelles with Unprecedented Stability Using Tunable Surfactants Derived from Cholic Acid

Area of Science:

• Biophysical Chemistry
• Materials Science
• Spectroscopy

Background:

• Bicelles are essential tools in nuclear magnetic resonance (NMR) spectroscopy for studying membrane proteins and lipid bilayers.
• Developing bicelles with enhanced stability and biomimetic properties is crucial for accurate in vitro studies.
• Sodium cholate derivatives offer potential for novel surfactant design.

Purpose of the Study:

• To synthesize and characterize novel sodium cholate-derived surfactants.
• To investigate the phase behavior of these surfactants with phospholipids (DMPC).
• To evaluate the formation and properties of magnetically alignable bicelles.

Main Methods:

• Synthesis of five novel surfactants by modifying sodium cholate with triethylene glycol chains.
• Preparation of aqueous mixtures of surfactants with 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC).
• Systematic study of phase behavior using 31P NMR spectroscopy.

Main Results:

• Carbamate-endcapped surfactants (SC-O^nC4, SC-O^tC4) formed magnetically alignable bicelles over wide temperature, lipid/surfactant ratio, and lipid content ranges.
• These carbamate-functionalized bicelles demonstrated exceptional thermal stability (0 to >90°C).
• Biomimetic lipid compositions and large 2H quadrupole splittings were achieved.

Conclusions:

• Novel carbamate-endcapped surfactants enable the formation of highly stable and versatile bicelles.
• These bicelles are suitable for biomimetic lipid compositions and advanced NMR studies.
• The findings expand the utility of bicelles in biophysical and structural biology research.