The effects of Ca 2+ on lipid diffusion

The effects of Ca 2+ on rotational and translational diffusion of lipids in multilamellar dimyristoylphosphatidylcholine (DMPC)-water systems were investigated by time-resolved phosphorescence anisotropy, steady-state fluorescence polarization and fluorescence recovery after photobleaching (FRAP) ex...

Full description

Saved in:
Bibliographic Details
Published inChemistry and physics of lipids Vol. 41; no. 3; pp. 183 - 194
Main Authors Blatt, Edward, Vaz, Winchil L.C.
Format Journal Article
LanguageEnglish
Published Elsevier Ireland Ltd 01.10.1986
Subjects
Online AccessGet full text

Cover

Loading…
More Information
Summary:The effects of Ca 2+ on rotational and translational diffusion of lipids in multilamellar dimyristoylphosphatidylcholine (DMPC)-water systems were investigated by time-resolved phosphorescence anisotropy, steady-state fluorescence polarization and fluorescence recovery after photobleaching (FRAP) experiments. Above the phase transition temperature ( T m ), addition of Ca 2+ caused a steady increase in the segmental motion of the phosphorescent probe, but resulted in slower diffusion of the fluorescent and lateral diffusion probes. The former result is attributed to changes in the structure of the lipid/water interface that affects the chromophore mobility on the phosphorescence time scale but does not reflect lipid motion. Below the phase transition temperature, slower diffusion of all probes were observed with increasing concentrations of Ca 2+, with sudden large changes occurring at [Ca 2+] ∼ 500 mM. This behaviour is attributed to association of Ca 2+ with the lipid phosphate groups and the exclusion of water molecules which results in tighter packing of lipids and smaller segmental motion, leading eventually to the immobilization of lipid molecules.
ISSN:0009-3084
1873-2941
DOI:10.1016/0009-3084(86)90021-6