Topological Study of the Conformational Interconversion Pathway and Molecular Folding

通过晶体学和理论研究确定了头孢酞菁的结构特征及其抗过氧化和自由基清除活性。结果表明，该大环生物碱的构象柔韧性与活性有关。我们计算了大环内酯类抗生素，红霉素A (EMA)，克拉霉素（CAM）和阿奇霉素（AZM）的构象变化，使用我们开发的适用于药物和植物化学化合物的综合构象搜索程序。根据得到的结果，我们预测大环后生产物的α-链（1-8位）明显比ω-链（9-13位）具有更高的柔韧性。实际上，在与任何生物大分子的配位络合物中，这些大环内酯在α-链而不是ω-链上的三维结构都具有多样性。在本工作中，我们基于核磁共振光谱研究了这些大环内酯类化合物的溶液结构。我们成功地量化了α-和ω-链的柔韧性。

Structural features of cepharanthine on its antiperoxidation and radical scavenging activities were determined by the crystallographic and theoretical studies. Our obtained results indicated that the conformational flexibility of this macrocyclic alkaloid was informative to the activities.We computed the conformational variations of macrolide antibiotics, erythromycin A (EMA), clarithromycin (CAM), and azithromycin (AZM), using our developed program of the comprehensive conformational search adaptive to the medicinal and phytochemical compounds. According to the obtained results, we predicted that the α-chains (at 1-8 positions) of the macrocyclic backborns obviously have higher flexibility than their ω-chains (at 9-13 positions). Actually, diversity of three-dimensional structure of these macrolides were observed at α-chain rather than at ω-chain, in the ligand-site complex with any biomacromolecules. In the present work, we investigated the solution structures of these macrolides, based on the NMR spectroscopy. We successfully quantified the flexibility of α- and ω-chains.