Conformation of flexibly linked triterpene dimers by using RDC-enhanced NMR spectroscopy
Abstract
Dimers of flexibly linked pentacyclic triterpene ursolic acid (UA) and its related frameworks such as asiatic acid (AA) and oleanolic acid (OA) have recently attracted significant attention due to their enhanced anti-cancer and anti-HCV activity compared to their respective monomers. Determination of conformation/inter-monomer orientation of these molecules is very important to understand their structure-activity relationship and to develop new scaffolds, which, however, is difficult through conventional NOE based solution-state NMR spectroscopy, due to lack of long-range NOEs. In the present work, we report a precise determination of conformation of two 1,2,3-triazole-linked triterpene dimer molecules, UA-AA and UA-OA, by employing one-bond Csbnd H residual dipolar couplings (RDCs) as additional long-range orientational restraints, measured in anisotropic PDMS/CDCl3 solvent medium.
- Publication:
-
Journal of Molecular Structure
- Pub Date:
- June 2018
- DOI:
- 10.1016/j.molstruc.2018.02.083
- Bibcode:
- 2018JMoSt1162...26L
- Keywords:
-
- RDC-Enhanced NMR;
- Conformation;
- Flexible triterpene dimer;
- MD simulations;
- Dynamics