Nishiyama Yoshiharu, Langan Paul, Wada Masahisa, Forsyth V Trevor
CERMAV-CNRS, BP 53, 38041 Grenoble CEDEX 9, France.
Acta Crystallogr D Biol Crystallogr. 2010 Nov;66(Pt 11):1172-7. doi: 10.1107/S0907444910032397. Epub 2010 Oct 20.
A series of cellulose crystal allomorphs has been studied using high-resolution X-ray and neutron fibre diffraction to locate the positions of H atoms involved in hydrogen bonding. One type of position was always clearly observed in the Fourier difference map (F(d)-F(h)), while the positions of other H atoms appeared to be less well established. Despite the high crystallinity of the chosen samples, neutron diffraction data favoured some hydrogen-bonding disorder in native cellulose. The presence of disorder and a comparison of hydrogen-bond geometries in different allomorphs suggests that although hydrogen bonding may not be the most important factor in the stabilization of cellulose I, it is essential for stabilizing cellulose III, which is the activated form, and preventing it from collapsing back to the more stable cellulose I.
利用高分辨率X射线和中子纤维衍射研究了一系列纤维素晶体变体，以确定参与氢键作用的氢原子的位置。在傅里叶差值图（F(d)-F(h)）中总能清晰地观察到一种位置类型，而其他氢原子的位置似乎不太确定。尽管所选样品具有高结晶度，但中子衍射数据表明天然纤维素中存在一些氢键无序现象。无序现象的存在以及不同变体中氢键几何结构的比较表明，虽然氢键可能不是纤维素I稳定化的最重要因素，但它对于稳定作为活化形式的纤维素III并防止其回塌到更稳定的纤维素I至关重要。
