A rigid helical peptide axle for a [2]rotaxane molecular machine

A series of peptido[2]rotaxanes have been designed which contain a rigid helix as a significant part of their axle. One such rotaxane has been used to construct a reversible molecular device, in which, by virtue of the size of the inner cavity of the wheel relative to the outer diameter of the peptide helix, a rotation of the wheel might occur concomitantly with its translation along the axle.