Application of the magnetization-inversion-transfer technique to the transport of 7Li+, 23Na+, and 39K+ ions through the gramicidin channel and the M2 delta transmembrane domain of the nicotinic acetylcholine receptor.

Overview

The magnetization-inversion-transfer NMR technique has been used to determine the activation enthalpy (delta H not equal to) for the transport of the 7Li+, 23Na+, and 39K+ ions through the gramicidin channel incorporated into vesicle membranes. The activation enthalpy obtained for the overall transport of the monovalent cations was found to be in agreement with the selectivity order and single-channel ion conductance values. Furthermore, the magnetization-inversion-transfer technique was also found to be applicable to the channel formed from a synthetic peptide having the same amino acid sequence as the M2 delta transmembrane segment of the nicotinic acetylcholine receptor.