鏈堆積導致的彎曲模量變化對Alamethicin離子通道活性的影響;The Effects of Chain Packing-induced Variation in Bending Modulus on the Ion Channel Activity of Alamethicin

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Title:	鏈堆積導致的彎曲模量變化對Alamethicin離子通道活性的影響;The Effects of Chain Packing-induced Variation in Bending Modulus on the Ion Channel Activity of Alamethicin
Authors:	吳崇吉;Wu, Chong-Ji
Contributors:	化學工程與材料工程學系
Keywords:	離子通道;彎曲模量;鏈堆積;Alamethicin;Ion Channel Activity;Bending Modulus;Chain Packing;Alamethicin
Date:	2020-08-17
Issue Date:	2020-09-02 15:14:51 (UTC+8)
Publisher:	國立中央大學
Abstract:	自發曲率(spontaneous curvature)和彎曲模量(bending modulus)是生物膜的兩個主要彈性特性。兩種彈性均受到鏈堆積的影響，其中，鏈堆積會影響彎曲模量。Keller和其團隊提及，膜的自發曲率決定了由肽（阿樂美黴素）形成的離子通道的活性。然而，由鏈堆積所引起膜的彎曲模量是否以及如何影響離子通道的活性仍然未知。為了回答這個問題，我們採用了由單不飽和脂質(DOPC和DOPS)以及由多不飽和脂質(di (18:2) PC 和DOPS)構成的脂質囊泡，因為兩種囊包組成的彎曲模量不同但自發曲率不同，並且觀察當囊泡組成發生變化時，Alamethicin離子通道的活性如何被調節。我們採用動態光散射和定向圓二色性來確定囊泡的大小和阿樂美黴素在脂質膜中的方向，同時通過將鈣敏感染劑fura-2包裹在囊泡中，通過螢光光譜法測量離子通道的活性，以檢測通過通道的鈣通量。我們發現受膜影響的彎曲模量對阿樂美黴素離子通道的活性是有影響的，這可能歸因於膜中脂質分子的堆積。;Spontaneous curvature and bending modulus are the two major elastic properties of biological membranes. Both of elastic properties are influenced by chain packing. Among them, the chain packing would influence bending modulus. Keller and coworkers reported that the spontaneous curvature of a membrane dictated the activity of the ion channels formed by the peptide, alamethicin. However, whether and how the chain packing-induced variation in bending modulus of a membrane affects the activity of ion channels remains unknown. To answer this question, we employed the lipid vesicles made of the monounsaturated lipids, DOPC and DOPS, as well as those made of polyunsaturated lipids, di (18:2) PC and DOPS, and observed how the activity of the alamethicin ion channels is modulated when the vesicle composition changes, since the vesicles of the two compositions differ in bending modulus but not in spontaneous curvature. We employed dynamic light scattering and orientation circular dichroism to determine the vesicle size and the orientation of alamethicin within the membranes, while the activity of the ion channels was measured with fluorescence spectroscopy via enveloping the calcium-sensitive dye, fura-2, into the vesicles to detect the calcium flux passing the channels. We found that the bending modulus of a membrane affected was influential to the activity of the alamethicin ion channels, which is possibly ascribable to the packing of the lipid molecules in a membrane.
Appears in Collections:	[National Central University Department of Chemical & Materials Engineering] Electronic Thesis & Dissertation

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