Division of Structural Biology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Miyagi, Japan.
Structural Glycobiology Team, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako 351-0198, Saitama, Japan.
Molecules. 2024 Feb 29;29(5):1072. doi: 10.3390/molecules29051072.
Ribitol (CHO) is an acyclic sugar alcohol that was recently identified in -mannose glycan on mammalian α-dystroglycan. The conformation and dynamics of acyclic sugar alcohols such as ribitol are dependent on the stereochemistry of the hydroxyl groups; however, the dynamics are not fully understood. To gain insights into the conformation and dynamics of sugar alcohols, we carried out comparative analyses of ribitol, d-arabitol and xylitol by a crystal structure database search, solution NMR analysis and molecular dynamics (MD) simulations. The crystal structures of the sugar alcohols showed a limited number of conformations, suggesting that only certain stable conformations are prevalent among all possible conformations. The three-bond scholar coupling constants and exchange rates of hydroxyl protons were measured to obtain information on the backbone torsion angle and possible hydrogen bonding of each hydroxyl group. The 100 ns MD simulations indicate that the ribitol backbone has frequent conformational transitions with torsion angles between 180∘ and ±60∘, while d-arabitol and xylitol showed fewer conformational transitions. Taking our experimental and computational data together, it can be concluded that ribitol is more flexible than d-arabitol or xylitol, and the flexibility is at least in part defined by the configuration of the OH groups, which may form intramolecular hydrogen bonds.
核糖醇（CHO）是一种环状糖醇，最近在哺乳动物α- 肌聚糖上的甘露糖聚糖中被发现。环状糖醇如核糖醇的构象和动力学取决于羟基的立体化学；然而，其动力学尚未完全了解。为了深入了解糖醇的构象和动力学，我们通过晶体结构数据库搜索、溶液 NMR 分析和分子动力学（MD）模拟对核糖醇、D-阿拉伯糖醇和木糖醇进行了比较分析。糖醇的晶体结构显示出有限数量的构象，这表明只有某些稳定的构象在所有可能的构象中占主导地位。通过测量三键偶合常数和羟基质子的交换率，我们获得了有关每个羟基的骨架扭转角和可能氢键的信息。100nsMD 模拟表明，核糖醇骨架具有频繁的构象转变，扭转角在 180°和±60°之间，而 D-阿拉伯糖醇和木糖醇的构象转变较少。综合我们的实验和计算数据，可以得出结论，核糖醇比 D-阿拉伯糖醇或木糖醇更具灵活性，这种灵活性至少部分由 OH 基团的构型定义，它们可能形成分子内氢键。
