亲脂性胞壁酰二肽的自旋标记脂肪酰衍生物的胶束形成及其掺入脂质体膜。

Micellar formation of spin-labeled fatty acyl derivatives of lipophilic muramyl dipeptides and their incorporation into liposomal membranes.

作者信息

Manabe H, Utsumi H, Kusama T, Hamada A

出版信息

Chem Phys Lipids. 1986 May;40(1):1-14. doi: 10.1016/0009-3084(86)90057-5.

Abstract

A lipophilic muramyl dipeptide (MDP) with a nitroxide moiety in its acyl chain (SL-MDP) and its N-methyl derivative (SL-methyl MDP) were synthesized. The SL-MDPs formed micelles (cmc, 0.1-0.3 mM). The ESR spectra of the SL-MDPs in phosphatidylcholine (PC) liposomes at 25 degrees C consisted of an anisotropic signal and three sharp lines, indicating that both SL-MDPs partitioned between membranes and aqueous phase. The amounts of the SL-MDPs in membranes depended on the phospholipid species and the cholesterol (Chol) content, but no appreciable difference was observed between SL-MDPs. The SL-MDPs partitioned well at 25 degrees C into egg yolk PC liposomes but not into pure dipalmitoylphosphatidylcholine (DPPC), suggesting that the incorporation may be related to the membrane fluidity. Chol enhanced the incorporation into both phospholipids. The mobilities of the SL-MDPs in the membranes were less than that of the corresponding spin-labeled fatty acid. Comparison of the mobilities among SL-MDPs, spin-labeled ganglioside and spin-labeled galactosylceramide showed that the hydrophilicity of the polar group may influence the immobilization of their acyl chains.

摘要

合成了一种在其酰基链中带有氮氧化物部分的亲脂性胞壁酰二肽（MDP）（SL-MDP）及其N-甲基衍生物（SL-甲基MDP）。SL-MDPs形成了胶束（临界胶束浓度，0.1 - 0.3 mM）。25℃时，SL-MDPs在磷脂酰胆碱（PC）脂质体中的电子顺磁共振光谱由一个各向异性信号和三条锐线组成，表明两种SL-MDPs都在膜和水相之间分配。膜中SL-MDPs的量取决于磷脂种类和胆固醇（Chol）含量，但在SL-MDPs之间未观察到明显差异。25℃时，SL-MDPs能很好地分配到蛋黄PC脂质体中，但不能分配到纯二棕榈酰磷脂酰胆碱（DPPC）中，这表明其掺入可能与膜流动性有关。胆固醇增强了其在两种磷脂中的掺入。SL-MDPs在膜中的流动性小于相应的自旋标记脂肪酸。比较SL-MDPs、自旋标记神经节苷脂和自旋标记半乳糖神经酰胺之间的流动性表明，极性基团的亲水性可能影响其酰基链的固定。