Related Experiment Video
Updated: Jun 21, 2026

Biomembrane Fabrication by the Solvent-assisted Lipid Bilayer (SALB) Method
Published on: December 1, 2015
Asymmetric distribution of cholesterol in unilamellar vesicles of monounsaturated phospholipids
Norbert Kucerka1, Mu-Ping Nieh, John Katsaras
1Canadian Neutron Beam Centre, National Research Council, Chalk River, Ontario K0J 1J0, Canada. Norbert.Kucerka@nrc.gc.ca
Abstract:
We have studied the effect of cholesterol on curved bilayers using 600 A unilamellar vesicles made of monounsaturated lipids. From small-angle X-ray scattering experiments we were able to detect an asymmetric distribution of lipid densities across certain bilayers. We discovered that, with the exception of diC24:1PC bilayers, monounsaturated diacylphosphatidylcholine lipids (diCn:1PC, n = 14, 16, 18, 20, and 22) form symmetric bilayers. However, the addition of 44 mol % cholesterol resulted in some of these bilayers (i.e., n = 14, 16, and 18) to become asymmetric, where cholesterol was found to distribute unequally between the bilayer's two leaflets. This finding is potentially of relevance to biological membranes made up of different types of lipids and whose local curvature may be dictated by lipid composition.
Related Concept Videos
Asymmetric Lipid Bilayer
Synthesis of Phosphatidylcholine in the ER Membrane
The major components of all eukaryotic cell...
Membrane Fluidity
Mosaic nature of the membrane
The mosaic characteristic of the membrane helps the plasma membrane remain fluid. The integral proteins and lipids exist as separate but loosely-attached molecules in the membrane. The membrane is a relatively...
Membrane Fluidity
Membrane Asymmetry Regulating Transporters
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
Assembly of the Lipid Bilayer in the ER
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...

