High pressure 2H-NMR study of the order and dynamics of selectively deuterated dipalmitoyl phosphatidylcholine in multilamellar aqueous dispersions.
High pressure 2H-NMR study of the order and dynamics of selectively deuterated dipalmitoyl phosphatidylcholine in multilamellar aqueous dispersions.
复制标题
多层水分散体中选择性氘化二棕榈酰磷脂酰胆碱的有序和动力学的高压 2H-NMR 研究。
DOI：
10.1016/s0006-3495(95)80288-2
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发表时间：
1995
影响因子：
3.4
通讯作者：
Jonas,J
中科院分区：
文献类型：
--
作者：
Peng,X;Jonas,A;Jonas,J
采用高压2H多脉冲核磁共振技术研究了压力对选择性氘化1,2-二棕榈酰- n-甘油-3-磷脂酰胆碱（DPPC）多层水分散体结构和动力学的影响。样品在2、9、13位的两个链上被氘化。在50℃下测量了三种氘化DPPC样品的氘谱线形状、自旋-晶格弛豫时间T1和自旋-自旋弛豫时间T2随压力从1 bar到5 kbar的变化。这个压力范围允许我们探索DPPC从液晶（LC）相到各种凝胶相的相行为，如凝胶I (P β)，凝胶II (L β)，凝胶III，凝胶X，以及交叉指状，凝胶I，凝胶相。压力对LC相和各种高压凝胶相的所有链段都有排序效应，SCD键序参数和第一矩M1随压力的增加表明了这一点。与相邻的凝胶相相比，凝胶i相的顺序最高。此外，在所有凝胶相中，碳-9链段的运动最受限制，而LC相中碳-2链段的运动最受限制。在LC阶段，各节段的T1和T2值随压力的增大而减小，表明相关时间快。同样，T1在Gel I和交错的Gel I凝胶相中随压力减小，但在Gel I /Gel II相转变时变为慢相关时间。（摘要删节250字）
High pressure 2H multipulse NMR techniques were used to investigate the effects of pressure on the structure and dynamics of selectively deuterated 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) multilamellar aqueous dispersions. The samples were deuterated on both chains at positions 2, 9, or 13. The deuterium lineshapes, the spin-lattice relaxation times, T1, and the spin-spin relaxation times, T2, were measured as a function of pressure from 1 bar to 5 kbar at 50 degrees C for the three deuterated DPPC samples. This pressure range permitted us to explore the phase behavior of DPPC from the liquid-crystalline (LC) phase through various gel phases such as the Gel I (P beta), Gel II (L beta), Gel III, Gel X, and the interdigitated, Gel i, gel phase. Pressure had an ordering effect on all chain segments both in the LC phase and various high pressure gel phases as indicated by the increase in SCD bond order parameter and the first moment, M1, with pressure. Compared with the adjacent gel phases, the Gel i phase had the highest order. Also, in all gel phases the carbon-9 segment of the chains had the most restricted motions in contrast to the LC phase, where the carbon-2 segment was the most restricted. In the LC phase, T1 and T2 values for all segments decreased with pressure, indicative of the fast correlation time regime. Similarly, T1 decreased with pressure in the Gel I and the interdigitated Gel i gel phases but changed to the slow correlation time regime at the Gel i/Gel II phase transition.(ABSTRACT TRUNCATED AT 250 WORDS)