One of the most exciting area of research in drug design concerns with the synthesis and 3D-structural characterisation of molecules containing peptidomimetics, since they can be expected to possess similar biological effects as their natural peptide counterparts, so that they could be used as therapeutics, with the potential, added advantages of higher metabolic stability, enhanced interactions with the receptor, and improved pharmacokinetic properties. In this review, we report the structural properties of the main constrained non coded aminoacids as examples of peptidomimetics or molecular tools able to induce specific conformations in bioactive peptide analogues.
