1,2-diacyl-phosphatidylcholine flip-flop measured directly by sum-frequency vibrational spectroscopy
1,2-diacyl-phosphatidylcholine flip-flop measured directly by sum-frequency vibrational spectroscopy
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DOI：
10.1529/biophysj.105.065672
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发表时间：
2005-10-01
影响因子：
3.4
通讯作者：
Conboy, JC
中科院分区：
文献类型：
--
作者：
Liu, J;Conboy, JC
和频振动光谱（SFVS）用于测量平面支撑脂质双层（ps）中1,2二myristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2- dipalmityl -sn-glycero-3-phosphocholine （DPPC）和1,2-二硬脂酰-snglycero-3-phosphocholine （dsc）的内在脂质翻转率。不对称pslb采用Langmuir-Blodgett/Langmuir-Schaefer方法，通过在一个lea中放置一个渗透脂质类似物来制备。委员会主席。SFVS通过测量2875 cm（-1）处CH3 vs强度随时间和温度的衰减，直接测量膜内天然脂质的不对称分布。测定了DMPC、DPPC和DSPC易位的平均活化能为220 kJ/mol。烷基链长度的减小导致触发器速率的显著增加，表现为Arrhenius指数前因子的增加。通过测定1,2-双棕榈酰基-n-甘油-3-磷酸乙醇胺-n，n-二甲基-n-（29,29,69,69-四甲基-49-胡椒酰基）（TEMPODPPC）的交换来研究脂质标记的效果。TEMPO-DPPC触发器的速率比DPPC慢一个数量级。测定的活化能为79 kJ/mol，与以前用电子自旋共振法测定的活化能相当。本研究的结果说明SFVS可以直接用于测量脂质触发器，而不需要荧光或自旋标记的脂质探针，这可以显著改变脂质易位率。
Sum-frequency vibrational spectroscopy (SFVS) is used to measure the intrinsic rate of lipid flip-flop for 1,2dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and 1,2-distearoyl-snglycero-3-phosphocholine ( DSPC) in planar-supported lipid bilayers (PSs). Asymmetric PSLBs were prepared using the Langmuir-Blodgett/Langmuir-Schaefer method by placing a perdeuterated lipid analog in one lea. et of the PSLB. SFVS was used to directly measure the asymmetric distribution of the native lipid within the membrane by measuring the decay in the CH3 vs intensity at 2875 cm(-1) with time and as a function of temperature. An average activation energy of 220 kJ/mol for the translocation of DMPC, DPPC, and DSPC was determined. A decrease in alkyl chain length resulted in a substantial increase in the rate of flip-flop manifested as an increase in the Arrhenius preexponential factor. The effect of lipid labeling was investigated by measuring the exchange of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-n,n-Dimethyl-n-(29,29,69,69-tetramethyl-49-piperidyl) (TEMPODPPC). The rate of TEMPO-DPPC flip-flop was an order-of-magnitude slower compared to DPPC. An activation energy of 79 kJ/mol was measured which is comparable to that previously measured by electron spin resonance. The results of this study illustrate how SFVS can be used to directly measure lipid flip-flop without the need for a fluorescent or spin-labeled lipid probe, which can significantly alter the rate of lipid translocation.