Chinese Journal of Magnetic Resonance

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A NMR STUDY ON PLANT CYCLOPEPTIDE DRYMARIN B

TENG Rong-wei, DING Zhong-tao, HE Yi-neng, YANG Cong-ren, WANG De-zu*   

  1. Kunming Institute of Botany, The Chinese Acdemy of Sciences, Kuming 650204, China
  • Received:2002-09-23 Revised:2003-01-28 Published:2003-03-05 Online:2003-03-05
  • About author:TENG Rong-wei,E-mail: tengrongwei@hotmail.com

Abstract:

Object  ]Severe spectral overlap often occurs in the 1H and 13C NMR spectra of plant cyclopeptides because of the similarity in chemical shifts of different amino acid residuals.  This paper aims to look for suitable NMR techniques for structural elucidation of plant cyclopeptides. Methods 2D NMR techniques such as  HMQC, HMBC, ROESY, and HMQC-TOCSY were used to study the structure of Drymarin B, a cyclopeptide isolated from the plant Drymaria diandra B1 (Caryophyllaceae).  Results  The 1H and 13C chemical shifts of the amino acid residuals (except for the quaternary carbons) can be assigned simultaneously using 2D HMQC-TOCSY  because this technique provides not only total proton correlation in the  F2 dimension but also total carbon correlation (except for the quaternary carbons) in the F1 dimension. The linkages among the anino acid residuals can be determined by  long range correlations from the HMBC spectra or NOEs from the ROESY or NOESY spectra. Conclusion   The 2D NMR techniques are  efficient tools for structural elucidation of plant cyclopeptides.

Key words: NMR, plant cyclopeptide, HMQC-TOCSY, assignments, Drymarin B

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