Hexagonal packing of lipid acyl chains and membrane plasticity

Area of Science:

• Lipid bilayer structure and dynamics
• Biophysics of cell membranes

Background:

• Biological membranes are composed of lipid bilayers.
• Understanding lipid packing is essential for membrane function.

Purpose of the Study:

• To investigate the flexibility of lipid layers based on acyl chain packing.
• To determine the suitability of different lipid packing structures for biological membranes.

Main Methods:

• Electron microscopy and electron diffraction were used to observe microcrystals of pure lipids.
• Observations were also conducted on wet bilayers of lecithin.

Main Results:

• Hexagonal packing of acyl chains (d100 = 4.17 A) in lipid microcrystals and bilayers demonstrated extreme flexibility.
• More crystalline polymethylene packings did not provide similar plasticity to lipid layers.

Conclusions:

• Hexagonal acyl chain packing provides the necessary plasticity for dynamic biological membranes.
• Crystalline lipid packings are unsuitable as structural matrices for dynamic biological membranes.