STRUCTURE OF THE CRYSTALLINE BILAYER IN THE SUBGEL PHASE OF DIPALMITOYLPHOSPHATIDYLGLYCEROL
STRUCTURE OF THE CRYSTALLINE BILAYER IN THE SUBGEL PHASE OF DIPALMITOYLPHOSPHATIDYLGLYCEROL
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DOI：
10.1021/bi00350a003
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发表时间：
1986-01-28
期刊：
影响因子：
2.9
通讯作者：
MCINTOSH, TJ
中科院分区：
文献类型：
--
作者：
BLAUROCK, AE;MCINTOSH, TJ
通过 X 射线衍射技术分析了二棕榈酰磷脂酰甘油 (DPPG) 亚凝胶相的结构。从亚凝胶相的高度定向 DPPG 样本记录的衍射延伸至 2-.ANG。解决。子午线上有尖锐的层状反射，其他反射位于一系列平行于子午线并在8-2°范围内穿过赤道的广角晶格线上。广角晶格线由以X射线胶片赤道为中心的径向锐反射以及一系列更宽的、偏离赤道的极大值组成。该晶格表明每个双层中的DPPG分子以二维倾斜晶格结晶，其尺寸为a=5.50°、b=7.96°和γ。 = 100.5°..这些倾斜晶格在双层之间并不规则排列。层状衍射分析表明双层在亚凝胶和凝胶(L.β)相中具有大约相同的厚度。在垂直于烃链的方向上，与正常的 L.beta 相比，这些链在亚凝胶相中明显更靠近。凝胶相，但与聚乙烯和结晶正烷烃中的链具有大致相同的分离。双层厚度、每个脂质分子的面积以及沿晶格线的强度分布都表明在亚凝胶相中烃链倾斜在 30 至 35° 之间。从法线到双层平面。我们的分析表明，在亚凝胶相中，链的侧向堆积与简单的长链烃（例如聚乙烯和结晶正烷烃）非常相似，而 DPPG 头基的影响导致链相对于双层法向倾斜。
The structure of the subgel phase of dipalmitoylphosphatidylglycerol (DPPG) has been analyzed by X-ray diffraction techniques. Diffraction recorded from highly oriented DPPG specimens in the subgel phase extends to 2-.ANG. resolution. There are sharp lamellar reflections on the meridian, and other reflections lie on a series of wide-angle lattice lines parallel to the meridian and crossing the equator in the range of 8-2 .ANG.. The wide-angle lattice lines consist of radially sharp reflections centered on the equator of the X-ray film and also a series of broader, off-equatorial maxima. The lattice indicate that the DPPG molecules in each bilayer crystallize in a two-dimensional oblique lattice with dimensions a = 5.50 .ANG., b = 7.96 .ANG., and .gamma. = 100.5.degree.. These oblique lattices are not regularly aligned from bilayer to bilayer. Analysis of the lamellar diffraction shows that the bilayer has about the same thickness in the subgel and gel (L.beta.) phases. In the direction normal to the hydrocarbon chains, the chains are significantly closer together in the subgel phase as compared to the normal L.beta. gel phase but have about the same separation as the chains in polyethylene and the crystalline n-alkanes. The bilayer thickness, area per lipid molecule, and intensity distribution along the lattice lines all indicate that in the subgel phase the hydrocarbon chains are tilted between 30 and 35.degree. from the normal to the bilayer plane. Our analysis indicates that in the subgel phase the lateral packing of chains is much the same as in simple long-chain hydrocarbons such as polyethylene and crystalline n-alkanes, whereas the influence of the DPPG head group causes the chains to tilt relative to the bilayer normal.