The gramicidin A channel: the energy profile for single and double occupancy in a head‐to‐head β6.33,3‐helical dimer backbone

The energy profile for Na+ in the channel formed by the gramicidin A β‐helical dimer backbone was computed introducing all the terms in the theory of intermolecular interactions. The effect of allowing the ion to reach its successive optimal positions shows the presence of a series of energy minima associated with different carbonyls. The presence of a second ion lowers the central barrier for the first one and facilitates its progression and exit. The energy profile for double occupancy indicates the presence of two symmetrical minima at about 13 Å from the center.