Steiner T, Koellner G, Ali S, Zakim D, Saenger W
Institut für Kristallographie, Freie Universität Berlin, Germany.
Biochem Biophys Res Commun. 1992 Nov 16;188(3):1060-6. doi: 10.1016/0006-291x(92)91339-r.
In contact with mother liquor, crystalline beta-cyclodextrin (beta-CD) hydrate has composition approximately beta-CD.12H2O. If crystals are dried at ambient conditions (18 degrees C, approximately 50% humidity), the unit cell volume diminishes approximately 30 to 50 A3. X-ray structure analysis of a dry crystal (0.89 A resolution, 4617 data, R = 0.059) showed the composition beta-CD.10.5 H2O, with approximately 5.5 water molecules in the beta-CD cavity (7 partially and 2 fully occupied sites) and approximately 5.0 between the beta-CD molecules. The positions of the beta-CD host and of most of the hydration waters are conserved during dehydration, but the occupancies of the waters in the beta-CD cavity diminish. Dry crystals put into solvent re-hydrate to the original form. The mechanism of de- and re-hydration is not evident.
与母液接触时，结晶β-环糊精（β-CD）水合物的组成约为β-CD·12H₂O。若晶体在环境条件（18℃，约50%湿度）下干燥，晶胞体积会减小约30至50 ų。对干燥晶体进行的X射线结构分析（分辨率0.89 Å，4617个数据，R = 0.059）显示其组成为β-CD·10.5H₂O，在β-CD空腔中有约5.5个水分子（7个部分占据位点和2个完全占据位点），在β-CD分子之间约有5.0个水分子。在脱水过程中，β-CD主体和大部分水合水分子的位置保持不变，但β-CD空腔中水分子的占有率降低。将干燥晶体放入溶剂中会重新水合至原始形态。脱水和再水合的机制尚不明确。
