MOLECULAR ARRANGEMENTS IN SPHINGOLIPIDS - CRYSTAL-STRUCTURE OF CEREBROSIDE
MOLECULAR ARRANGEMENTS IN SPHINGOLIPIDS - CRYSTAL-STRUCTURE OF CEREBROSIDE
复制标题
DOI：
10.1016/0009-3084(77)90033-0
复制
发表时间：
1977-01-01
影响因子：
3.4
通讯作者：
SUNDELL, S
中科院分区：
文献类型：
--
作者：
PASCHER, I;SUNDELL, S
本文描述了一种复杂的膜糖脂的单晶分析。脑苷脂（β- D-半乳糖基-N-（2-D-羟基十八烷酰基）-D-二氢鞘氨醇，C42 H83 O 9 N. 1/2C 2 H5 OH），属单斜晶系，空间群P21，a = 11.202，B = 9.262，c = 46.46。和β= 99.00 °在不对称单元中有2个独立的分子，部分与非晶体学对称性相关。通过直接方法测定结构并精确至R = 0.116。分子以典型的双层排列方式堆积，相邻的双层被结晶的乙醇分子隔开。糖环的平面几乎平行于层界面，这使得分子呈铲子的形状。与极性神经酰胺部分一起，半乳糖头基在每层的极性区域内形成广泛的H键横向网络。链条倾斜49 °。朝这个极地边界移动链的平行堆叠通过鞘氨醇链的弯曲直至2个独立分子中的C原子5和6来实现。另一种烃链堆积是早期未知的混合型（HS 2）。具有平行之字形平面的链被布置在褶片中。这些片层交替地含有脂肪酸和鞘氨醇链，它们具有相互垂直的链平面取向。
The single crystal analysis of a complex, membrane glycolipid is described. Cerebroside (.beta.-D-galactosyl-N-(2-D-hydroxyoctadecanoyl)-D-dihydrosphingosine, C42H83O9N .cntdot. 1/2C2H5OH) an important constituent of plasma membranes, crystallizes in the monoclinic spacegroup P21 with a = 11.202, b = 9.262, c = 46.46 .ANG. and .beta. = 99.00.degree.. There are 2 independent molecules in the asymmetric unit partly related by a non-crystallographic symmetry. The structure was determined by direct methods and refined to R = 0.116. The molecules pack in a typical bilayer arrangement with adjacent double layers separated by ethanol molecules of crystallization. The planes of the sugar rings are turned almost parallel to the layer interface which gives the molecules the shape of a shovel. Together with the polar ceramide part, the galactose head groups form an extensive lateral network of H-bonds within the polar region of each layer. The chains tilt by an angle of 49.degree. towards this polar boundary. A parallel stacking of the chains is achieved by a bend of the sphingosine chain as far up as C atom 5 and 6 in the 2 independent molecules. The alteral hydrocarbon chain packing is of an earlier unknown hybrid type (HS2). Chains with parallel zigzag planes are arranged in pleated sheets. These sheets contain alternatively fatty acid and sphingosine chains which have a mutually perpendicular chain plane orientation.