Experimental tests for protrusion and undulation pressures in phospholipid bilayers.
Experimental tests for protrusion and undulation pressures in phospholipid bilayers.
复制标题
磷脂双层中突出和波动压力的实验测试。
DOI：
10.1021/bi00027a002
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发表时间：
1995
期刊：
影响因子：
2.9
通讯作者：
Simon,SA
中科院分区：
文献类型：
--
作者：
McIntosh,TJ;Advani,S;Burton,RE;Zhelev,DV;Needham,D;Simon,SA
摘要：理论处理预测相邻双层膜之间的强熵压可以由整个双层膜的热诱导弯曲波动引起的平面外运动引起[Harbich， W., & Helfrich， W.（1984）化学。理论物理。血脂36,39-63；Evans， E. A, & Parsegian, VA (1986) Proc. Natl。学会科学。[j]张建军，张建军，张建军，等。（1992）J.物理学报。为了确定这些运动对磷脂双层之间排斥压的相对贡献，采用渗透应力/ x射线衍射法测量总排斥压的范围和大小，并采用微移管法测量含溶血磷脂酰胆碱双层和多不饱和二叠四烯酰基磷脂酰胆碱（DAPC）双层的弯曲模量。在凝胶相中，等摩尔溶血磷脂酰胆碱掺入磷脂酰胆碱双分子层导致烃链从相对的单层变为交叉，但没有明显改变过量缓冲液的平衡流体间距，其控制值为12 Á。与此相反，等摩尔溶血磷脂酰胆碱掺入液晶磷脂酰胆碱双分子层后，排斥压范围明显增大，平衡流体分离从15增加到28 Á，双分子层弯曲模量从5.1 × 10~ 13降低到1.3 × 10~ 13 erg。液晶DAPC双层具有平衡流体分离（20 Á）和弯曲模量（2.8 × 10~ 13 erg）的中间值。对这些数据的分析表明：(1)与水化压力相比，熵压的相对重要性在很大程度上取决于双层结构的组成和结构；(2)在大压力或小流体间距下，突出压力可能对总排斥力有贡献；(3)排斥力波动压力与吸引范德华压力共同作用。是决定在低和/或零施加压力下液晶双层流体间距的主要因素。
Revised Manuscript Received May 5, 1995® abstract: Theoretical treatments predict that strong entropic pressures between adjacent bilayer membranes can arise from out of plane motions caused by eitherthermally induced bending undulations of the entire bilayer [Harbich, W., & Helfrich, W.(1984) Chem. Phys. Lipids 36, 39—63; Evans, E. A., & Parsegian, VA (1986) Proc. Natl. Acad. Sci. USA 83, 7132—7136] or protrusions of individual lipid molecules from the bilayer surface [Israelachvili, J. N., & Wennerstrom, H.(1992) J. Phys. Chem. 96, 520-531], To determine the relative contributions of these motions to the repulsive pressure between phospholipid bilayers, the osmotic stress/X-ray diffraction method was used to measure the range and magnitude of the total repulsive pressure, and micropipet methods were used to measure the bending moduli of phosphatidylcholine bilayers containing lysophosphatidylcholine and polyunsaturateddiarachidonoylphos-phatidylcholine (DAPC) bilayers. In the gel phase, incorporation of equimolar lysophosphatidylcholine into phosphatidylcholine bilayers caused the hydrocarbon chains from apposing monolayers to interdigitate, but did not appreciably change the equilibrium fluid spacing in excess buffer from its control value of 12 Á. In contrast, the incorporation of equimolar lysophosphatidylcholine into liquid-crystalline phase phosphatidylcholine bilayers markedly increasedthe range of the repulsive pressure so that equilibrium fluid separation increased from 15 to 28 Á, and also decreased the bilayer bending modulus from 5.1 x 10~ 13 to 1.3 x 10-13 erg. Liquid-crystalline DAPC bilayers had intermediate values of both equilibrium fluid separation (20 Á) and bending modulus (2.8 x 10~ 13 erg). Analysis of these data indicates that (1) the relative importance of entropic pressures compared to the hydration pressure depends strongly on the composition and structure of the bilayer,(2) the protrusion pressure may contribute to the total repulsive pressure at large pressures or small fluid spacings, and (3) the repulsiveundulation pressure, together with the attractive van der Waals pressure, is a primary factor in determining the fluid spacing at low and/or zero applied pressures in liquid-crystalline bilayers.