Publikace detail

Structural, Dynamic and Mechanical Properties of POPC at Low Cholesterol Concentration Studied in Pressure/Temperature Space

Rok: 2003

Druh publikace: článek v odborném periodiku

Název zdroje: European Biophysics Journal with Biophysics Letters

Název nakladatele: Springer

Místo vydání: NEW YORK, USA

Strana od-do: 575-585

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
cze
eng	Structural, Dynamic and Mechanical Properties of POPC at Low Cholesterol Concentration Studied in Pressure/Temperature Space	We have studied the structural, dynamic and mechanical properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC)/cholesterol (up to 25 mol%) binary mixtures by small-angle X-ray scattering. From the dependence of the transition pressure we derived a value of 19 kJ/mol for the transition enthalpy DeltaH(m) of POPC in excess water. With increasing cholesterol concentration, DeltaH(m) drops to about 7 kJ/mol at 20 mol% cholesterol. Time-resolved pressure-scan (p-scan) and temperature-jump (T-jump) experiments reveal that at low cholesterol content (< 5-8 mol%) the fluidity and also the bilayer compressibility increase remarkably. In contrast, at concentrations between 5 and 25 mol% cholesterol the bilayer becomes again more rigid and the lipid bilayer spacing increases about 2 &ANGS. Theses changes are attributed to the onset of phase separation between liquid disordered and liquid ordered phases. The fluid-fluid miscibility gap for this mono-unsaturated lecithin species is strongly enlarged compared with saturated lecithins.	cholesterol;phosphatidylcholine;pressure scan;temperature jump;phase separation

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