NMR solution structure of gramicidin A complex with caesium cations

Abstract
The conformation of the 1:1 complex of [Val1] gramicidin A with caesium cations has been determined in methanol/chloroform (1:1) solution by 2‐dimensional1H‐NMR spectroscopy. The molecular structure was found to be a right‐handed antiparallel double helical dimer ↑↓ππLD7.2with 7.2 residues per turn, which incorporates two caesium cations.