Janaswamy Srinivas, Chandrasekaran Rengaswami
Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, IN 47907-2009, USA.
Carbohydr Res. 2005 Apr 11;340(5):835-9. doi: 10.1016/j.carres.2004.12.035.
X-ray intensity data from a polycrystalline sample of debranched arabinan, -->5)-alpha-L-Ara(f)-(1-->, have been obtained using a powder diffractometer in order to determine its three-dimensional structure. The observed peaks index on a monoclinic cell with a=5.444(7), b=6.395(10), c=8.680(5) A, and gamma=99.6(3) degrees , V=298 A3. One 2-fold helix along the c-axis can be accommodated in the unit cell. Molecular and packing models have been analyzed using the seven C-2'-endo/C-3'-endo allomorphs originally proposed by Radha and Chandrasekaran [Carbohydr. Res. 1997, 298, 105]. The generated powder pattern matches closely with the observed diffraction only for one C-2'-endo model. In this structure, the three main chain conformation angles are in the trans domains, there are no intra-chain hydrogen bonds, and the packing arrangement is stabilized by inter-chain O-3-H...O-2 bonds.
已使用粉末衍射仪获取了去支链阿拉伯聚糖→5)-α-L-阿拉伯糖基-(1→多晶样品的X射线强度数据，以确定其三维结构。观察到的峰在单斜晶胞上标定指数，晶胞参数为a = 5.444(7) Å、b = 6.395(10) Å、c = 8.680(5) Å，γ = 99.6(3)°，V = 298 ų。沿c轴的一个二重螺旋可容纳在晶胞中。已使用Radha和Chandrasekaran最初提出的七种C-2'-内型/C-3'-内型异质同晶体分析了分子和堆积模型[《碳水化合物研究》1997年，298卷，105页]。仅对于一种C-2'-内型模型，生成的粉末图谱与观察到的衍射紧密匹配。在该结构中，三个主链构象角处于反式结构域，不存在链内氢键，堆积排列通过链间O-3-H...O-2键得以稳定。
