Comparative effects of cholesterol and cholesterol sulfate on hydration and ordering of dimyristoylphosphatidylcholine membranes.
AUTOR(ES)
Faure, C
RESUMO
The comparative effect of cholesterol (CH) versus cholesterol sulfate (CS) on dimyristoylphosphatidylcholine (DMPC) membranes has been investigated by optical microscopy, freeze-fracture electron microscopy, x-ray diffraction, and solid state 2H and 31P nuclear magnetic resonance (NMR). The sulfate analogue extends the lamellar phase domain toward high water contents, and substitution of 30 mol % CH by CS in DMPC lamellae induces the trapping of 30 wt % additional water. The greater swelling of the CS-containing systems is evidenced by determination of lamellar repeat distances at maximal hydration: 147 +/- 4 A and 64 +/- 2 A in the presence of CS and CH, respectively. 2H-NMR of heavy water demonstrates that CS binds approximately 12 more water molecules at the interface than CH whereas NMR of deuterium-labeled DMPC chains reveals that 30 mol % CS orders the membrane as 15 mol % CH at high temperature and disorders much more than CH at low temperatures. The various effects of CS versus CH are discussed by taking into account attractive Van der Waals forces and repulsive steric/electrostatic interactions of the negatively charged sulfate group.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1225063Documentos Relacionados
- Differential effects of cholesterol and lanosterol on artificial membranes.
- Oxygen permeability of phosphatidylcholine--cholesterol membranes.
- Cholesterol incorporation into bacterial membranes.
- Sulfate transport in Penicillium chrysogenum plasma membranes.
- Cholesterol-induced fluid-phase immiscibility in membranes.
