NON-CHANNEL FORMS OF GRAMICIDIN IN LIPID MEMBRANE BY DQC ESR

通过 DQC ESR 测定脂膜中非通道形式的短杆菌肽

• 批准号: 8363972
• 负责人: BORIS G DZIKOVSKI
• 金额: $ 0.57万
• 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/8363972
• 关键词: Address; Complex; Equilibrium; Fingerprint; Funding; Gel; Gramicidin; Grant; Hand; Head; Label; Left; Lipids; Measures; Membrane Lipids; Minor; Molecular Conformation; National Center for Research Resources; Octanols; Phase; Positioning Attribute; Principal Investigator; Research; Research Infrastructure; Resources; Series; Site; Source; Spin Labels; Structure; System; Technology; United States National Institutes of Health; Work; cost; dimer; gramicidin A; monomer; saturated fat

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. In previous work on channel formation using spin labeled Gramicidin A (GAsl) we found that the non-channel form prevails in the gel phase of mismatching lipids (DPPC, DSPC). We have now addressed the assignment of non-channel forms and studied the complex equilibrium in the gramicidin/lipid system, which includes channels (i.e. head-to-head dimers [HHD]), non-channel dimers, and monomers. To study non-channel forms of spin labeled GA, which can aggregate, we labeled two different sites on the same gramicidin molecule, instead of measuring the distance between spin labels attached at the same position on both dimer-forming molecules. This intramolecular distance between the spin labels could be used as a fingerprint of the particular conformation. Interactions between spin labels on different gramicidin molecules were eliminated by substantially diluting the double spin-labeled gramicidin by unlabeled gramicidin. Several new spin labeled gramicidin compounds were synthesized and used. In octanol, gramicidin exists mainly as a double helical (DH) left-handed antiparallel dimer, and we determined interspin distances for this structure. GAD with both N- and C-termini labeled and GALN, single-labeled at the N-terminus, substantially impair their propensity to HHD formation. In most lipids we observed two different conformations of GAD. The interspin distance in the main fraction (20.0¿) is consistent with the monomeric state. Double helices (31.6¿, exactly as in octanol) are a minor component with the fraction changing in the saturated lipid series in the following order: DLPC<DMPC<DSPC<DPPC. We also showed by DQC that both gramicidin monomers and DH exist in all studied lipid phases only in aggregates.

该副本是利用资源的众多研究子项目之一 由NIH/NCRR资助的中心赠款提供。对该子弹的主要支持 而且，副投影的主要研究员可能是其他来源提供的 包括其他NIH来源。列出的总费用可能 代表subproject使用的中心基础架构的估计量， NCRR赠款不直接向子弹或副本人员提供的直接资金。 在使用旋转标记的Gramicidin A（GASL）的通道形成的工作中，我们发现非通道形式在不匹配脂质的凝胶相（DPPC，DSPC）中占上风。现在，我们已经解决了非通道形式的分配，并研究了gramicidin/脂质系统中的复合物等效物，其中包括通道（即头到头二聚体[HHD]），非通道二聚体和单体。为了研究可以汇总的自旋标记的GA的非通道形式，我们将两个不同位点标记在同一gramicidin分子上，而不是测量在两个二聚体形成分子上相同位置附着的自旋标记之间的距离。自旋标签之间的分子内距离可以用作特定构象的指纹。通过未标记的gramicidin实质性稀释双自旋标记的gramicidin，消除了不同法米霉素分子上的自旋标记之间的相互作用。合成并使用了几种新的旋转标记的谷霉素化合物。在辛醇中，谷霉素主要作为双螺旋（DH）左手二聚体存在，我们确定了该结构的旋转缝隙。在N末端标记的N-和C-termini标记和galn的GAD显着损害其对HHD形成的可靠性。在大多数脂质中，我们观察到GAD的两种不同考虑。主级分（20.0€）中的旋转距离与单体状态一致。双螺旋（31.6¿，与辛烷值完全一样）是一个次要组件，其分数按以下顺序在饱和脂质系中变化：DLPC <dmpc <dmpc <dspc <dspc <dppc。我们还向DQC表明，仅在聚集体中，所有研究的脂质阶段都存在格米霉素单体和DH。