Theoretical conformational analysis of the Gramicidin a transmembrane channel. I. Helix sense and energetics of head‐to‐head dimerization

Conformational energy calculations are presented for the head‐to‐head dimerized β helices for Gramicidin A transmembrane channel structures. The calculations take into account both left‐ and right‐handed β helices, and various side‐chain conformations. The energetics of the dimerization is studied by considering various docking geometries. It is concluded from these vacuum‐energy calculations that the lowest energy conformation for the channel dimer is that comprised of left‐handed β helices.