A new monofluorinated phosphatidylcholine forms interdigitated bilayers
A new monofluorinated phosphatidylcholine forms interdigitated bilayers
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DOI：
10.1016/s0006-3495(98)77626-x
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发表时间：
1998-10-01
影响因子：
3.4
通讯作者：
Blazyk, J
中科院分区：
文献类型：
--
作者：
Hirsh, DJ;Lazaro, N;Blazyk, J
16-以16-羟基棕榈酸为原料，用二乙氨基三氟化硫合成了氟代棕榈酸。然后将该单氟化脂肪酸用于制备作为二棕榈酰磷脂酰胆碱（DPPC）的氟化类似物的1-棕榈酰-2-[16-氟棕榈酰]-磷脂酰胆碱（F-DPPC）。令人惊讶的是，根据差示扫描量热法和红外光谱法的判断，我们发现F-DPPC的相变温度（T-m）接近50摄氏度，比其非氟化对应物DPPC高出10摄氏度。在DPPC中观察到的预转变在F-PPC中不存在。常规的固态N-MR实验表明，F-DPPC在凝胶相中形成完全交叉的双分子层。电子顺磁共振实验表明，在低于Tm时，F-DPPC的烃链比DPPC的烃链受到更大的运动限制。X-射线散射实验证实，凝胶相F-DPPC的厚度和堆积类似于庚三醇诱导的叉指型DPPC。F-DPPC是第一种含有相同长度的sn-1：和sn-2酯连接的脂肪酰基链的磷酸甘油酯，其在不存在诱导剂如醇的情况下自发地形成凝胶状态的交叉双层。
16-Fluoropalmitic acid was synthesized from 16-hydroxypalmiticacid using diethylaminosulfur trifluoride. This monofluorinated fatty acid then was used to make 1-palmitoyl-2-[16-fluoropalmitoyl]-phosphatidylcholine (F-DPPC) as a fluorinated analog of dipalmitoylphosphatidylcholine (DPPC). Surprisingly, We found that the phase transition temperature (T-m) of F-DPPC occurs near 50 degrees C, similar to 10 degrees C higher than its nonfluorinated counterpart, DPPC, as judged by both differential scanning calorimetry and infrared spectroscopy. The pretransition observed for DPPC is absent in F-PPC. A combination of REDOR, (r) under bar otational-(e) under bar cho uble-(r) under bar esonance,an conventional solid-state N-MR experiments demonstrates that F-DPPC forms a fully interdigitated bilayer in the gel phase. Electron paramagnetic resonance experiments show that below T-m, the hydrocarbon chains of F-DPPC are more motionally restricted than those of DPPC. X-ray scattering experiments confirm that the thickness and packing of gel phase F-DPPC is similar to that of heptanetriol-induced interdigitated DPPC. F-DPPC is the first phosphoglyceride containing sn-l: and sn-2 ester-linked fatty acyl chains of equal length that spontaneously forms interdigitated bilayers in the gel state in the absence of inducing agents such as alcohols.