Deuterium NMR investigation of ether- and ester-linked phosphatidylcholine bilayers.
Deuterium NMR investigation of ether- and ester-linked phosphatidylcholine bilayers.
复制标题
醚连接和酯连接的磷脂酰胆碱双层的氘核磁共振研究。
DOI：
10.1021/bi00339a018
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发表时间：
1985
期刊：
影响因子：
2.9
通讯作者：
Griffin,RG
中科院分区：
文献类型：
--
作者：
Ruocco,MJ;Makriyannis,A;Siminovitch,DJ;Griffin,RG
M. J. Ruocco，A. Makriyannis，* D. Siminovitch和RG Griffin* 弗朗西斯比特国家磁铁实验室，马萨诸塞州理工学院，剑桥，马萨诸塞州02139接收于1984年12月20日摘要：在-33至50 ℃范围内，研究了作为温度函数的特定头基和链氘代酯和醚连接的磷脂酰胆碱双层的氘核磁共振（2 H NMR）谱。头基氘代双十六烷基磷脂酰胆碱（[a-2 H2] DHPC）双层产生的线形和自旋晶格弛豫时间类似于其酯连接的对应物，双棕榈酰磷脂酰胆碱（[a-2 H2] DPPC），在高温涟漪和La双层相。这些结果表明醚键对磷酸胆碱头基a-C_2 H_2链段的动力学和取向顺序没有影响。在所有温度下，链氘代的1，2 [1 '，1'-2H2] DHPC双层的2 H NMR光谱与1，2 [2，2/-2H2] DPPC双层相比表现出减小的光谱宽度。DHPC在45 ℃氘代烷基链光谱的最显著特征是观察到四个独立的四极分裂从-亚甲基的烷基链段，相比之下，从DPPC的酰基链的-亚甲基的三个等极分裂先前报道。在DHPC上进行的自旋-晶格弛豫实验表明，两个较小的和两个较大的四极分裂分配到单独的烷基链，分别。氘代头基[a-2 H2] DHPC的低温（<-20 ℃）凝胶相光谱仍然比[a-2 H2] DPPC观察到的那些窄一个数量级。链标记的DHPC的线形在20至-20 ℃的40 ℃范围内对温度不变，而在DPPC中，线形在0 ℃以下有实质性变化。这些观察结果可以通过形成相互交叉的DHPC双层凝胶相来解释，其中脂质分子的轴向扩散持续到比DPPC轴向扩散停止的温度低至少20 ℃的温度（~ 20 ℃）。
M. J. Ruocco, A. Makriyannis,* D. J. Siminovitch, and RG Griffin* Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 Received December 20, 1984 abstract: Deuterium nuclear magnetic resonance(2H NMR) spectra of specifically head-group-and chain-deuterated ester-and ether-linked phosphatidylcholine bilayers were studied as a function of temperature over the range-33 to 50 C. Head-group-deuterated dihexadecylphosphatidylcholine ([a-2H2] DHPC) bilayers yield line shapes and spin-lattice relaxation times similar to those observed for its ester-linked counterpart, dipalmitoylphosphatidylcholine ([a-2H2] DPPC), in the high-temperature ripple and La bilayer phases. Theseresults indicate the ether linkage has no effect on the dynamics or the orientational order at the a-C2H2 segment of the phosphocholine head group. At all temperatures, the 2H NMR spectra of chain-deuterated 1, 2 [1', 1'-2H2] DHPC bilayers exhibit a reduced spectral width compared to 1, 2 [2\2/-2H2] DPPC bilayers. The most significant feature of the deuterated alkyl chain spectrum of DHPC at 45C is the observation of four separate quadrupolarsplittings from the-methylene segments of the alkyl chains, in comparison to the threequadrupolar splittings reported previously from the-methylene segments of the acyl chains of DPPC. Spin-lattice relaxationexperiments performed on DHPC suggest an assignment of the two smaller and the two larger quadrupolar splittings to separate alkyl chains, respectively. Lowtemperature (<-20 C) gel-phase spectra of deuterated head-group [a-2H2] DHPC remain an order of magnitude narrower than those observed for [a-2H2] DPPC. Line shapes of chain-labeled DHPC are invariant to temperature over the 40 C range from 20 to-20 C, whereas in DPPC, there is a substantial change in the line shape below 0 C. These observations may be explained by the formation of an interdigitated DHPC bilayer gel phase in which axialdiffusion of the lipid molecule persists down to temperatures at least 20 C below the temperature at which axialdiffusion of DPPC ceases (~