Cholesterol favors the emergence of a long-range autocorrelated fluctuation pattern in voltage-induced ionic currents through lipid bilayers
The present paper was aimed at evaluating the effect of cholesterol (CHO) on the voltage-induced lipid 22 Q5 pore formation in bilayer membranes through a global characterization of the temporal dynamics of 23 the fluctuation pattern of ion currents. The bilayer model used was black lipid membranes...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2013 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/1517 |
| Acceso en línea: | http://hdl.handle.net/11336/1517 |
| Access Level: | acceso abierto |
| Palabra clave: | BLACK LIPID MEMBRANES CHOLESTEROL DETRENDED FLUCTUATION ANALYSIS IONIC CURRENT LIPID PORES https://purl.org/becyt/ford/1.6 https://purl.org/becyt/ford/1 |
| Sumario: | The present paper was aimed at evaluating the effect of cholesterol (CHO) on the voltage-induced lipid 22 Q5 pore formation in bilayer membranes through a global characterization of the temporal dynamics of 23 the fluctuation pattern of ion currents. The bilayer model used was black lipid membranes (BLMs) of 24 Q6 palmitoyloleoylphosphatidylethanolamine and palmitoyloleoylphosphatidylcholine (POPE:POPC) at a 7:3 25 molar ratio in the absence (BLM0) or in the presence of 30 (BLM30), 40 (BLM40) or 50 (BLM50) mol% of cholesterol 26 with respect to total phospholipids. Electrical current intensities (I)weremeasured in voltage (ΔV) clamped condi- 27 tions at ΔV ranging between 0 and ±200 mV. The autocorrelation parameter α derived from detrended fluc- 28 tuation analysis (DFA) on temporal fluctuation patterns of electrical currents allowed discriminating 29 between non-correlated (α = 0.5, white noise) and long-range correlated (0.5 b α b 1) behaviors. The in- 30 crease in |ΔV| as well as in cholesterol content increased the number of conductance states, the magnitude of con- 31 ductance level, the capacitance of the bilayers and increased the tendency towards the development of long-range 32 autocorrelated (fractal) processes (0.5 b α b 1) in lipid channel generation. Experimentswere performed above the 33 phase transition temperature of the lipidmixtures, but compositions used predicted a superlattice-like organization. 34 This leads to the conclusion that structural defects other than phase coexistencemay promote lipid channel forma- 35 tion under voltage clamped conditions. Furthermore, cholesterol controls the voltage threshold that allows the per- 36 colation of channel behavior where isolated channels become an interconnected network. |
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