Cuccia L A, Morin F, Beck A, Hébert N, Just G, Lennox R B
Department of Chemistry, McGill University, Montréal, PQ, Canada.
Chemistry. 2000 Dec 1;6(23):4379-84. doi: 10.1002/1521-3765(20001201)6:23<4379::aid-chem4379>3.0.co;2-m.
Solid-state 2H NMR spectroscopy was used to study and characterize the conformation and order of bolaform lipid membranes. A series of 2H-labeled bolaform phosphatidylcholines has been synthesized and their properties compared to a [D4]dimyristoylphosphatidylcholine (DMPC) and a [D8]-32 macrocyclic phosphatidylcholine. 31P NMR measurements establish that the aqueous dispersions of these lipids adopt lamellar phases. Computational dePakeing was used to extract the spectrum of the oriented system from spectra consisting of a superposition of randomly oriented domains in an unoriented sample. A large (> 90 %) and constant value for the normalized segmental order parameter (Smol) was observed for all positions along the diacyl chain of the bolaform lipids and only a small population (< 10%) of a less ordered conformer was observed. The less ordered conformer is assigned to the looping conformation on the basis of comparison with the deuterated macrocyclic phospholipid which has an enforced loop in its diacyl chain. The predominant population(> 90%) of the bolaform lipids is assigned to a highly ordered, spanning conformer.
固态2H核磁共振光谱法用于研究和表征bola型脂质膜的构象和有序性。已合成了一系列2H标记的bola型磷脂酰胆碱，并将它们的性质与[D4] - 二肉豆蔻酰磷脂酰胆碱（DMPC）和[D8] - 32大环磷脂酰胆碱进行了比较。31P NMR测量确定这些脂质的水分散体呈现层状相。使用计算解卷积从由未取向样品中随机取向域的叠加组成的光谱中提取取向系统的光谱。对于bola型脂质的二酰基链上的所有位置，观察到归一化链段序参数（Smol）的大（> 90％）且恒定的值，并且仅观察到少量（<10％）的无序构象体。基于与在其二酰基链中具有强制环的氘代大环磷脂的比较，将较少有序的构象体指定为环化构象。bola型脂质的主要群体（> 90％）被指定为高度有序的跨接构象体。
