Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
J Phys Chem B. 2011 Aug 25;115(33):9948-54. doi: 10.1021/jp205663z. Epub 2011 Aug 2.
An atomic-level insight into the functioning of articular cartilage would be useful to develop prevention strategies and therapies for joint diseases such as osteoarthritis. However, the composition and structure of cartilage and their relationship to its unique mechanical properties are quite complex and pose tremendous challenges to most biophysical techniques. In this study, we present an investigation of the structure and dynamics of polymeric molecules of articular cartilage using time-resolved solid-state NMR spectroscopy during dehydration. Full-thickness cartilage explants were used in magic-angle spinning experiments to monitor the structural changes of rigid and mobile carbons. Our results reveal that the dehydration reduced the mobility of collagen amino acid residues and carbon sugar ring structures in glycosaminoglycans but had no effect on the trans-Xaa-Pro conformation. Equally interestingly, our results demonstrate that the dehydration effects are reversible, and the molecular structure and mobility are restored upon rehydration.
深入了解关节软骨的功能对于开发预防关节疾病（如骨关节炎）的策略和疗法非常有用。然而，软骨的组成和结构及其与独特机械性能的关系非常复杂，给大多数生物物理技术带来了巨大的挑战。在这项研究中，我们使用时间分辨固态 NMR 光谱法在脱水过程中研究了关节软骨聚合分子的结构和动力学。全厚软骨标本用于魔角旋转实验，以监测刚性和可移动碳的结构变化。我们的结果表明，脱水降低了胶原蛋白氨基酸残基和糖胺聚糖中环糖结构的流动性，但对反-Xaa-Pro 构象没有影响。同样有趣的是，我们的结果表明，脱水效应是可逆的，在重新水合时，分子结构和流动性得到恢复。
