Peptide-based rotaxanes and catenanes: an emerging class of supramolecular chemistry systems

[2]Rotaxanes are interlocked molecular systems in which the cavity of a macrocycle (wheel) is threaded by a linear compound (axle). The axle is held in place principally by a sterically demanding moiety (stopper) at each end. If the two ends of a rotaxane are covalently linked together, then an assembly of two intertwined macrocycles (termed [2]catenane) is generated. Although rotaxanes and catenanes have been extensively investigated by several research groups, only a limited amount of studies has been devoted to these systems when a peptide molecule characterizes either the axle or the wheel(s) (or both). The purpose of this short conceptual overview is to summarize recent findings on synthetic and naturally occurring peptide-based [2]rotaxanes, [3]rotaxanes, and [2]catenanes and discuss future prospects for the research in this emerging area of supramolecular chemistry.