Detection of coexisting fluid phospholipid phases by equilibrium Ca2+ binding: peptide-poor L alpha and peptide-rich HII phase coexistence in gramicidin A'/phospholipid dispersions.
Detection of coexisting fluid phospholipid phases by equilibrium Ca2+ binding: peptide-poor L alpha and peptide-rich HII phase coexistence in gramicidin A'/phospholipid dispersions.
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通过平衡 Ca2 结合检测共存的流体磷脂相：缺乏肽的 L α 和富含肽的 HII 相共存于短杆菌肽 A/磷脂分散体中。
DOI：
10.1021/bi00248a002
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发表时间：
1994
期刊：
影响因子：
2.9
通讯作者：
Feigenson,GW
中科院分区：
文献类型：
--
作者：
Dibble,AR;Feigenson,GW
修订稿于 1994 年 8 月 23 日收到• 摘要：通过平衡 Ca2+ 结合技术研究了三种短杆菌肽 A'/磷脂混合物的等温相行为。磷脂组分是1，2-二油酰基-。 sn-甘油-3-磷酸丝氨酸 (DOPS)、l-棕榈酰-2-油酰-s «-甘油-3-磷酸丝氨酸 (POPS) 或 POPS/l-棕榈酰-2-油酰-s «-甘油-3-磷酸胆碱 (POPC)，摩尔比恒定为 1/4。使用发色高亲和力 Ca2+ 螯合剂，在 20°C 下测量与一或两个短杆菌肽 A'/磷脂液相和少量 Ca（磷脂酰丝氨酸）2 凝胶相平衡的大量含水游离 Ca2+ 浓度 [Ca2+]* f，作为组成的函数。通过在两相共存的组合物范围内[Ca2+]* f 的不变性来检测两个短杆菌肽A'/磷脂流体相的共存。两个共存相的组成由 [Ca2+]* f 不变性开始和结束时的组成决定。对于每种短杆菌肽A'/磷脂混合物，我们估计贫短杆菌肽相的组成为0.03-0.04摩尔分数短杆菌肽A'，而富含短杆菌肽相的组成为0.13-0.14摩尔分数短杆菌肽A'。通过低角度X射线衍射对这些相的表征表明，在每种情况下，缺乏短杆菌肽的相是La相，而富含短杆菌肽的相是Hu相。通过低角 X 射线衍射测定，发现短杆菌肽 A'/POPC 混合物在约 23°C 的等温相行为与其他短杆菌肽 A'/磷脂混合物的等温相行为相似。除了当磷脂成分是DOPS时之外，在所有情况下31P核磁共振波谱均未能检测到富含短杆菌肽的Hu相。讨论了平衡 Ca2+ 结合技术在检测磷脂相分离（包括 La'/La2 相分离）中的一般适用性。大多数生物膜由脂质和蛋白质的复杂混合物组成。多种实验技术已经提供了许多类型的细胞和模型膜中脂质和蛋白质成分显着横向异质性的证据[有关评论，请参见 Edidin (1992) 和 Tocanne (1992)]。细胞膜中的一些横向异质性似乎是由与细胞骨架元素的相互作用或通过添加或耗尽
Revised Manuscript Received August 23, 1994• abstract: The isothermal phase behavior of three gramicidin A'/phospholipid mixtures was investigated by an equilibrium Ca2+-binding technique. The phospholipid component was l, 2-dioleoyl-. sn-glycero-3-phosphoserine (DOPS), l-palmitoyl-2-oleoyl-s «-glycero-3-phosphoserine (POPS), or POPS/l-palmitoyl-2-oleoyl-s «-glycero-3-phosphocholine (POPC) at a constant mole ratio of 1/4. The bulk aqueous free Ca2+ concentration,[Ca2+]* f, in equilibrium with one or two gramicidin A'/phospholipid fluid phases and a small amount of the Ca (phosphatidylserine) 2 gel phase, was measured as a function of compositionat 20 C by use of chromophoric high-affinity Ca2+ chelators. The coexistence of two gramicidin A'/phospholipid fluid phases was detected by an invariance in [Ca2+]* f over the range of compositions throughout which the two phases coexist. The compositions of the two coexisting phases are determined by the compositions at which the invariance in [Ca2+]* f begins and ends. With each of the gramicidin A'/phospholipid mixtures, we estimate that the composition of the gramicidin-poor phase is 0.03-0.04 mole fraction gramicidin A'and the composition of the gramicidin-rich phase is 0.13-0.14 mole fraction gramicidin A'. Characterization of these phases by low-angle X-ray diffraction revealed that, in each case, the gramicidin-poor phase is an La phase and the gramicidin-rich phase isan Hu phase. The isothermal phase behavior of gramicidin A'/POPC mixtures at~ 23 C, as determined by low-angle X-ray diffraction, was found to be similar to that of the other gramicidin A'/phospholipid mixtures. 31P nuclear magnetic resonance spectroscopy failed to detect the gramicidin-rich Hu phase in all cases except when the phospholipid component was DOPS. The general applicability of the equilibrium Ca2+-binding technique to the detection of phospholipid phase separations, including La ‘/La2 phase separations, is discussed.Most biological membranes are composed of complex mixtures of lipids and proteins. Evidence for significant lateral heterogeneity of lipid and protein components in many types of cell and model membranes has been provided by a wide variety of experimental techniques [for reviews, see Edidin (1992) and Tocanne (1992)]. Some of these lateral hetero-geneities in cell membranes appear to be caused by interactions with cytoskeletal elements or by the addition or depletion of
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短杆菌肽 A/卵磷脂系统中的疏水错配。
影响因子：
2.9
作者：
Watnick,PI;Chan,SI;Dea,P
通讯作者：
Dea,P
短杆菌肽 A 在共存的液体相和凝胶磷脂相之间的分配。
DOI：
10.1016/0005-2736(93)90400-t
发表时间：
1993
期刊：
Biochimica et biophysica acta
影响因子：
--
作者：
Dibble,AR;Yeager,MD;Feigenson,GW
通讯作者：
Feigenson,GW
磷脂酰乙醇胺中短杆菌肽诱导的六方 HII 相形成的热力学、运动和结构方面。
影响因子：
2.9
作者：
J. Killian;B. de Kruijff
通讯作者：
B. de Kruijff
影响因子：
2.9
作者：
FEIGENSON, GW
通讯作者：
FEIGENSON, GW
影响因子：
3.4
作者：
KINGSLEY, PB;FEIGENSON, GW
通讯作者：
FEIGENSON, GW