کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9757698 | 1496386 | 2005 | 17 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Intermolecular interactions of lysobisphosphatidic acid with phosphatidylcholine in mixed bilayers
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کلمات کلیدی
1,2-dipalmitoylphosphatidylcholineNBD-PCpretransition temperatureDPPCPoPCMLVLBPADPHDSCΔH1-palmitoyl-2-oleoyl-phosphatidylcholine - 1-پالمیتویل-2-اولئویل-فسفاتیدیل کولین1,6-diphenyl-1,3,5-hexatriene - 1،6-دیفنیل-1،3،5-هگزیدریلlysobisphosphatidic acid - اسید لیسوبیسفسفیدیدlarge unilamellar vesicle - بزرگ کیسه بیضهenthalpy change - تغییرات آنتالپیmain phase transition temperature - دمای انتقال فاز اصلیSurface pressure - فشار سطحFluorescence spectroscopy - فوتولومینسانس یا فلوئورسانس یا فسفرسانسLUV - لووMultilamellar vesicle - پاپیون چندگانهDifferential scanning calorimetry - کالریمتری روبشی افتراقی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی (عمومی)
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چکیده انگلیسی
Lysobisphosphatidic acid (LBPA) can be regarded to represent a unique derivative of phosphatidylglycerol. This lipid is highly enriched in late endosomes where it can comprise up to 10-15 mol% of all lipids and in these membranes, LBPA appears to be segregated into microdomains. We studied the thermotropic behavior of pure dioleoyl-LBPA mono- and bilayers using Langmuir-lipid monolayers, electron microscopy, differential scanning calorimetry (DSC), and fluorescence spectroscopy. LBPA formed metastable, liquid-expanded monolayers at an air/buffer interface, and its compression isotherms lacked any indication for structural phase transitions. Neat LBPA formed multilamellar vesicles with no structural transitions or phase transitions between 10 and 80 °C at a pH range of 3.0-7.4. We then proceeded to study mixed LBPA/dipalmitoylphosphatidylcholine (DPPC) bilayers by DSC and fluorescence spectroscopy. Incorporating increasing amounts of LBPA (up to XLBPA (molar fraction) = 0.10) decreased the co-operativity of the main transition for DPPC, and a decrease in the main phase transition as well as pretransition temperature of DPPC was observed yet with no effect on the enthalpy of this transition. In keeping with the DSC data for DPPC, 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC)/LBPA mixed bilayers were more fluid, and no evidence for lateral phase segregation was observed. These results were confirmed using fluorescence microscopy of Langmuir-lipid films composed of POPC and LBPA up to XLBPA = 0.50 with no evidence for lateral phase separation. As late endosomes are eminently acidic, we examined the effect of lowering pH on lateral organization of mixed PC/LBPA bilayers by DSC and fluorescence spectroscopy. Even at pH 3.0, we find no evidence of LBPA-induced microdomain formation at LBPA contents found in cellular organelles.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemistry and Physics of Lipids - Volume 133, Issue 1, January 2005, Pages 51-67
Journal: Chemistry and Physics of Lipids - Volume 133, Issue 1, January 2005, Pages 51-67
نویسندگان
Juha M. Holopainen, Tim Söderlund, Juha-Matti Alakoskela, Matti Säily, Ove Eriksson, Paavo K.J. Kinnunen,