NMR STUDIES OF D-ERYTHRO-AND L-THREO-C16-CERAMIDES UNDER PHYSIOLOGICAL CONDITI

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。神经酰胺本身，或作为鞘磷脂和鞘糖脂的脂骨架，是细胞膜的结构和功能成分。神经酰胺参与多种细胞过程的调节：分化、生长抑制、细胞衰老和细胞凋亡。我们已经注意到神经酰胺的电子结构与它们在体内和体外的活性有很强的相关性。然而，由于神经酰胺在水中的溶解性较差，其在水溶液中的结构在生理条件下从未被研究过。我们已经克服了这一困境：(I)将神经酰胺与一种精选的氢化阳离子表面活性剂混合，或(Ii)修改其疏水界面。这些研究的目的是开发一个通用的实验核磁共振模型系统来研究天然神经酰胺及其非天然同系物在37℃，pH从4.5-8.5的水中的溶液结构。在这里，我们提供了有史以来第一组实验核磁共振数据，显示了D-红血球神经酰胺和L-苏氨酸-C16-神经酰胺在不同环境条件下结构的实质性变化。用T1弛豫法和PFG-核磁共振扩散法研究了该体系的动力学。目前的发展方向是神经酰胺-蛋白质相互作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Ceramide itself, or as the lipid backbone of sphingomyelin and glycosphingolipid, is a structural and functional component of cell membranes. Ceramides are involved in the regulation of several cellular processes: differentiation, growth suppression, cell senescence and apoptosis. We have noticed a strong correlation between electronic structure of ceramides and their in vivo and in vitro activity. However, due to poor solubility of ceramides in water, their structure in aqueous solution has never been investigated under physiological conditions. We have overcome this predicament by: (i) mixing ceramide with a selected deuterated cationic surfactant, or (ii) modifying its hydrophobic interface. The purpose of these studies was to develop a universal experimental NMR model system to examine solution structure of naturally occurring ceramides and their unnatural congeners in water at 37C, with pH varied from 4.5 - 8.5. Here we present a first ever set of experimental NMR data showing substantial changes in the structure of D-erythro- and L-threo-C16-ceramides exposed to a different environmental conditions. The dynamics of the system were investigated using T1 relaxation and PFG-NMR diffusion measurements. Current developments are oriented towards ceramide-protein interactions.