Related Experiment Video
Updated: Jun 7, 2026

Fluorescence Recovery after Merging a Droplet to Measure the Two-dimensional Diffusion of a Phospholipid Monolayer
Published on: October 15, 2015
Lateral diffusion in sphingomyelin bilayers
A V Filippov1, M A Rudakova, B V Munavirov
1Kazan (Volga Region) Federal University, 18, Kazan 420008, Russia. andfil@ltu.se
Abstract:
Sphingomyelin (SM) is an important lipid of eukaryotic cellular membranes and neuronal tissues. We studied lateral diffusion in macroscopically oriented bilayers of synthetic palmitoylsphingomyelin (PSM) and natural sphingomyelins of egg yolk (eSM), bovine brain (bSM) and bovine milk (mSM) by pulsed field gradient NMR (PFG NMR) in the temperature range 45-60 °C. We found that the mean values of lateral diffusion coefficients (LDCs) of SMs are 1.9-fold lower compared with those of dipalmitoylphosphatidylcholine (DPPC), which is similar in molecular structure. This discrepancy could be explained by the characteristics of intermolecular SM interactions. The LDCs of different SMs differ: egg SM is most similar to PSM; both of them have a 10% higher LDC value compared with the other two natural SMs. Besides, all natural SMs show a complicated form of the spin-echo diffusion decay (DD), which is an indicator of a distribution of LDC values in bilayers. This peculiarity is explained by the broad distributions of hydrocarbon chain lengths of the natural SMs studied here, especially mSM and bSM. We confirmed the relationship between chain length and LDC in the bilayers by computer analysis of a set of (1)H NMR spectra obtained by scanning the value of the pulsed field gradient. There is a correlation between lower LDC values and SM molecules with longer acyl chains. The most probable mechanisms by which long-chain SM molecules decrease their lateral diffusion relative to the average value are protrusion into the other side of the bilayer or lateral separation into areas that diverge with their LDCs.
More Related Videos
05:56Spot Variation Fluorescence Correlation Spectroscopy for Analysis of Molecular Diffusion at the Plasma Membrane of Living Cells
Published on: November 12, 2020
15:10From Fast Fluorescence Imaging to Molecular Diffusion Law on Live Cell Membranes in a Commercial Microscope
Published on: October 9, 2014
Related Concept Videos
Protein Diffusion in the Membrane
Asymmetric Lipid Bilayer
Diffusion
Diffusion
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...
Passive Diffusion: Overview and Kinetics
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...