Observation of inverted cubic phase in hydrated dioleoylphosphatidylethanolamine membranes.
Observation of inverted cubic phase in hydrated dioleoylphosphatidylethanolamine membranes.
复制标题
水合二油酰磷脂酰乙醇胺膜中倒立立方相的观察。
DOI：
10.1021/bi00407a014
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发表时间：
1988
期刊：
影响因子：
2.9
通讯作者：
Tilcock,CP
中科院分区：
文献类型：
--
作者：
Shyamsunder,E;Gruner,SM;Tate,MW;Turner,DC;So,PT;Tilcock,CP
加拿大温哥华不列颠哥伦比亚大学生物化学系，1987年12月2日收到；1988年1月28日收到修订稿摘要：我们报道了用小角X射线衍射法观察到1，2-二油酰甘油-3-磷乙醇胺(DOPE)水分散体中的倒立方相。DOPE是研究生物体系中非片层相的一种范式：随着温度的升高，它呈现出从片状相(La)到倒六方相(Hn)的相变。观察到当掺杂分散体从La相稳定的2℃加热到HN相稳定的15℃时，该转变发生得很快。我们报道了当脂质分散体在-5到15℃之间快速循环数百次时，诱导形成的结晶学上定义良好的立方晶格。一旦形成，立方晶格在4℃下稳定数周，并表现出与脂-水体系中其他立方相相同的显著亚稳性。X射线衍射表明，立方晶格与Pn3m或Pn3空间群最一致。立方诱导后的脂类纯度测试表明，脂类至少有98%的纯度。立方晶格可以通过在-30℃到2℃之间循环几次来破坏立方晶格和重新设置系统。立方晶格的形成动力学取决于样品的热历史、整体水浓度和循环的极端温度。立方相的存在可能是氢形成脂的一般特征，并根据脂单分子层的自发曲率半径进行了讨论[Gruner，S.M.(1985)Proc.娜塔莉。阿卡德。SCI。美国82,3665-3669]，
Department of Biochemistry, University of British Columbia, Vancouver V6T 1W5, Canada Received December 2, 1987; Revised Manuscript Received January 28, 1988 abstract: We report the observation of an inverted cubic phase in aqueous dispersions of 1, 2-dioleoyljvz-glycero-3-phosphoethanolamine (DOPE) by small-angle X-ray diffraction. DOPE is a paradigm in the study of nonlamellar phases in biological systems: it exhibits a well-known phase transition from the lamellar (La) to the inverted hexagonal phase (Hn) as the temperature is raised. The transition is observed to occur rapidly when a DOPE dispersion is heated from 2 C, where the La phase is stable, to 15 C, where the Hn phase is stable. We report on the induction of a crystallographically well-defined cubic lattice that is slowly formed when the lipid dispersion is rapidly cycled between-5 and 15 C hundreds of times. Once formed, the cubic lattice is stable at 4 C for several weeks and exhibits the same remarkable metastability that characterizes other cubic phases in lipid-water systems. X-ray diffraction indicates that the cubic lattice is most consistent with either the Pn3m or Pn3 space group. Tests of lipid purity after induction of the cubic indicate the lipid is at least 98% pure. The cubiclattice can be destroyed and the system reset by cycling thespecimen several times between-30 and 2 C. The kinetics of the formation of the cubic are dependent on the thermal history of the sample, overall water concentration, and the extreme temperatures of the cycle. The presence of cubic phases may be a general feature of Hirforming lipids and is discussed in terms of the spontaneous radius of curvature of lipid monolayers [Gruner, S. M.(1985) Proc. Natl. Acad. Sci. USA 82, 3665-3669],