Design, synthesis, structure and properties of an α-helix cap template derived from N-[(2S)-2-chloropropionyl]-(2S)-Pro-(2R)-Ala-(2S,4S)-4-thioPro-OMe which initiates α-helical structures
作者:David Gani、Arwel Lewis、Trevor Rutherford、John Wilkie、Iain Stirling、Thierry Jenn、Martin D. Ryan
DOI:10.1016/s0040-4020(98)00991-0
日期:1998.12
were characterised by NMR spectroscopy and restrained simulated annealing. In deuterochloroform solution at low temperature, separate sets of NMR signals were observed for two rapidly interconverting helical conformational isomers of the thioether macrocycle which possessed an appended trialkylammonium ion. A similar time-averaged conformation was also observed in aqueous solution. At −80 °C in d2-dichloromethane
一种基于消除所有羰基偶极子在过渡状态下同时排列的要求的策略,从而导致N-[(2S)-2-氯丙酰基]-(2S)-Pro-(2R)-环化Zila-Bragg型α-螺旋肽启动子模板的Ala-(2S,4S)-4-thioPro-OMe成功。12-元大环模板的每个酰胺键都以反式-旋转异构体形式存在。通过扩展C端制备模板的衍生物,并通过NMR光谱和受限的模拟退火对其进行表征。在低温的氘代三氯甲烷溶液中,观察到分别具有两个附加的三烷基铵离子的硫醚大环的两个快速相互转化的螺旋构象异构体的NMR信号集。在水溶液中也观察到类似的时间平均构象。2-二氯甲烷的构象交换速率足够慢,以得到每种异构体的共振分配和NOE数据。在次要异构体(40%)中,模板的四个羰基氧氢键受体以α-螺旋构象排列,而在主要构象中,Pro 2羰基偶极与其他三个偶极反排列。因此,构象异构体在一个羰基的取向上不同。分子模型计算表明,三烷基铵盐和羰