【作者】 滕荣伟； 穆青； 何以能； 周俊； 李朝明； 丁中涛； 王德祖； 杨崇仁；

【Author】 Rongwei Teng, Qing Mu, Yineng He, Jun Zhou, Chaoming Li,Zhongtao Ding, Dezu Wang, Congren Yang (Kunming Institute of Botany, CAS, Kuming, 650204, e-mail: tengrongwei@hotmail.com)

【机构】 中国科学院昆明植物研究所；

【摘要】 植物环肽的¹H和¹³C NMR图谱中,谱峰高度重叠,结构解析比较困难。本文以二蕊荷莲豆环肽B为例讨论了现代2D NMR新技术,特别是2D HMQC-TOCSY技术,在植物环肽结构解析中的应用。2D NMQC-TOCSY技术在氢谱方向和碳谱方向分别提供每一个氨基酸自旋系统内氢和除季碳外碳的全相关信息,从而将每个氨基酸残基的NMR信号相互区分开来。氨基酸残基的连接顺序信息可用HMBC、NOESY或ROESY图谱获得。更多还原

【Abstract】 NMR signals overlapped with each other seriously in 1H and 13C NMR spectrum of plant cyclopeptides due to similarity of chemical shifts in different amino acid residuals. Unambiguous assignments are difficult without TOCSY pulse sequence. In general, one amino acid residual is one independent spin system in NMR term. Proton signals due to different amino acid residuals can be distinguished from each other easily in TOCSY spectrum because TOCSY can provide proton total correlation for every independent spin systems. Both proton and carbon signals (except quaternary carbon) can be assigned simultaneously in 2D HMQC-TOCSY spectra because 2D HMQC-TOCSY can provide not only total proton correlation in F, dimension but also total carbon correlation (except quaternary carbon) in F, dimension. Linkages of amino acid residuals can be determined by the information from HMBC, ROESY or NOESY spectra. Drymarin B, a plant cyclopeptide isolated from Drymaria diandra B1. (Caryophyllaceae), was taken as example to explain the application of these 2D NMR techniques.更多还原