2 D ELDOR: LIQUID ORDERED PHASE & LIPID MULTILAMELLAR VESICLE MEMBRANES

2 D ELDOR：液态有序相

• 批准号: 8363947
• 负责人: ANTONIO COSTA-FILHO
• 金额: $ 0.37万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8363947
• 关键词: Behavior; Chemicals; Cholestanes; Cholesterol; Choline; Diffuse; Diffusion; Disease; Environment; Exhibits; Funding; Grant; Ions; Label; Lipid Bilayers; Lipids; Liquid substance; Measures; Membrane; Membrane Lipids; Membrane Microdomains; Methods; Modeling; Motion; National Center for Research Resources; Phase; Physiological; Play; Principal Investigator; Proteins; Publishing; Research; Research Infrastructure; Resources; Role; Source; Spin Labels; Sterols; Stimulus; Structure; Technology; United States National Institutes of Health; Vesicle; Visual; Work; cost; two-dimensional

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The fluid mosaic model played an important role for understanding the dynamic behavior in biomembranes. The model postulated that the membranous proteins are diffusing and/or fluctuating in a homogeneous lipid medium, i.e. two-dimensional liquid. However, recent studies on biomembranes have revealed that physiological function is firmly related to the heterogeneous environment in the lipid membranes. When some physico-chemical stimuli occur, such as interactions with ions, proteins, and sterols, then heterogeneous phases frequently appear in biomembranes, yielding microdomains, which have been termed lipid rafts. In fact, in model bilayer membranes of lipids and cholesterol (Chol), one can find liquid ordered (Lo) phases as well as liquid disordered or liquid crystalline (Lc) phases. We have developed 2D-ELDOR for measuring rotational diffusion as well as translational diffusion in lipid vesicle membranes. Our stud ies revealed the dynamic structures of the Lo and Lc phases in membranes of pure lipids (Lc) and lipid/Cholesterol (Lo), in which a chain labeled lipid a headgroup labeled lipid, or a spin labeled cholestane CSL was incorporated. Creation and annihilation of the spectral cross-peaks was observed in the spectra from Lc and from Lo phases respectively. Thus, visual inspection of cross peaks in the 2D-ELDOR spectra provides a convenient way to distinguish them. In the Lo phase, acyl chains undergo a faster rotational diffusion and higher ordering than in the Lc phase. On the other hand, the choline headgroup in the Lo phase exhibits faster motion and reduced ordering as compared to the Lc phase. Also, the translational diffusion rates in the Lo phase are significantly reduced in the presence of Chol. Thus 2D-ELDOR is demonstrated to be a powerful method to study the dynamic structure of membranes. This work has been published and extensive studies as a function of cholesterol concentration have been completed.

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 流体马赛克模型对理解生物膜的动力学行为起着重要作用。该模型假定膜蛋白在均匀的脂类介质中扩散和/或波动，即二维液体。然而，最近对生物膜的研究表明，生理功能与脂膜中的异质环境密切相关。当一些物理化学刺激发生时，如与离子、蛋白质和甾醇的相互作用，生物膜中经常会出现非均相，产生微域，这被称为脂筏。事实上，在脂类和胆固醇(Chol)的模型双层膜中，人们可以发现液体有序(LO)相以及液体无序或液晶(LC)相。我们已经开发了2D-Eldor，用于测量脂泡膜中的旋转扩散和平移扩散。我们的研究揭示了纯脂(LC)和脂/胆固醇(LO)膜中LO和LC相的动态结构，其中链标记的脂质是标记的头基团标记的脂类，或自旋标记的胆烷CSL。在LC和LO相的光谱中分别观察到光谱交叉峰的产生和湮灭。因此，目视检查2D-Eldor光谱中的交叉峰提供了一种方便地区分它们的方法。在LO相中，酰基链经历了比在LC相中更快的旋转扩散和更高的有序度。另一方面，与LC相相比，LO相中的胆碱头基表现出更快的运动速度和更少的有序性。此外，在CHOL的存在下，LO相中的平移扩散速率显著降低。因此，2D-Eldor被证明是研究膜动态结构的有力手段。这项工作已经发表，作为胆固醇浓度函数的广泛研究已经完成。