Concentration-driven growth of model protocell membranes.
Concentration-driven growth of model protocell membranes.
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DOI：
10.1021/ja310382d
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发表时间：
2012-12-26
影响因子：
15
通讯作者：
Szostak, Jack W.
中科院分区：
文献类型：
--
作者：
Budin, Itay;Debnath, Anik;Szostak, Jack W.
第一个原始细胞膜可能是由前生物环境中可用的脂肪酸和相关单链脂质组装而成的。在复杂的细胞机器进化之前，自发的原始细胞膜生长和分裂必须是在特定环境条件下这些分子的内在物理化学性质的结果。根据化学和物理环境的性质，脂肪酸可以在几个不同的相之间分配，包括可溶性单体、胶束和层状囊泡。在这里，我们解决脂肪酸聚集的浓度依赖性，这主要是由熵考虑决定的。我们结合物理和光谱技术定量区分脂肪酸相，包括使用荧光脂肪酸类似物 Laurdan，其发射光谱对胶束和层状聚集体之间的结构差异敏感。我们发现单体-聚集体转变很大程度上遵循分子聚集的特征伪相模型，但聚集相的组成也依赖于浓度。在高于临界聚集浓度的低两亲物浓度下，囊泡与显着比例的胶束共存，而更浓缩的溶液有利于层状囊泡相。我们随后表明，通过溶剂蒸发或添加过量脂质，两亲物浓度增加时，胶束-囊泡平衡可用于驱动预先存在的囊泡的生长。我们提出了一个原始环境驱动的细胞周期的简单模型，其中原始细胞膜的生长是由蒸发浓缩引起的，然后是剪切力或光化学诱导的分裂。
The first protocell membranes may have assembled from fatty acids and related single-chain lipids available in the prebiotic environment. Prior to the evolution of complex cellular machinery, spontaneous protocell membrane growth and division had to result from the intrinsic physicochemical properties of these molecules, in the context of specific environmental conditions. Depending on the nature of the chemical and physical environment, fatty acids can partition between several different phases, including soluble monomers, micelles, and lamellar vesicles. Here we address the concentration dependence of fatty acid aggregation, which is dominated by entropic considerations. We quantitatively distinguish between fatty acid phases using a combination of physical and spectroscopic techniques, including the use of the fluorescent fatty acid analogue Laurdan, whose emission spectrum is sensitive to structural differences between micellar and lamellar aggregates. We find that the monomer–aggregate transition largely follows a characteristic pseudophase model of molecular aggregation but that the composition of the aggregate phase is also concentration dependent. At low amphiphile concentrations above the critical aggregate concentration, vesicles coexist with a significant proportion of micelles, while more concentrated solutions favor the lamellar vesicle phase. We subsequently show that the micelle–vesicle equilibrium can be used to drive the growth of pre-existing vesicles upon an increase in amphiphile concentration either through solvent evaporation or following the addition of excess lipids. We propose a simple model for a primitive environmentally driven cell cycle, in which protocell membrane growth results from evaporative concentration, followed by shear force or photochemically induced division.
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影响因子：
2.7
作者：
Parasassi, T;Krasnowska, EK;Gratton, E
通讯作者：
Gratton, E
DOI：
10.1039/f29767201525
发表时间：
1976-01-01
期刊：
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS II
影响因子：
--
作者：
ISRAELACHVILI, JN;MITCHELL, DJ;NINHAM, BW
通讯作者：
NINHAM, BW
DOI：
10.1073/pnas.0805086105
发表时间：
2008-09-09
影响因子：
11.1
作者：
Mansy, Sheref S.;Szostak, Jack W.
通讯作者：
Szostak, Jack W.
影响因子：
3.9
作者：
Fukuda, H;Goto, A;Walde, P
通讯作者：
Walde, P
影响因子：
64.8
作者：
DEAMER, DW
通讯作者：
DEAMER, DW