title: Designing supramolecular structures from models of cyclic peptide scaffolds with heterocyclic constraints.
abstract: Cyclic peptides containing oxazole and thiazole heterocycles have been examined for their capacity to be used as scaffolds in larger, more complex, protein-like structures. Both the macrocyclic scaffolds and the supramolecular structures derived therefrom have been visualised by molecular modelling techniques. These molecules are too symmetrical to examine structurally by NMR spectroscopy. The cyclic hexapeptide ([Aaa-Thz](3), [Aaa-Oxz](3)) and cyclic octapeptide ([Aaa-Thz](4), [Aaa-Oxz](4)) analogues are composed of dipeptide surrogates (Aaa: amino acid, Thz: thiazole, Oxz: oxazole) derived from intramolecular condensation of cysteine or serine/threonine side chains in dipeptides like Aaa-Cys, Aaa-Ser and Aaa-Thr. The five-membered heterocyclic rings, like thiazole, oxazole and reduced analogues like thiazoline, thiazolidine and oxazoline have profound influences on the structures and bioactivities of cyclic peptides derived therefrom. This work suggests that such constrained cyclic peptides can be used as scaffolds to create a range of novel protein-like supramolecular structures (e.g. cylinders, troughs, cones, multi-loop structures, helix bundles) that are comparable in size, shape and composition to bioactive surfaces of proteins. They may therefore represent interesting starting points for the design of novel artificial proteins and artificial enzymes.
authors.affiliation: Centre for Drug Design and Development, Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Lucke
authors.forename: J D A
authors.initials: JD
authors.lastname: Tyndall
authors.forename: Y
authors.initials: Y
authors.lastname: Singh
authors.forename: D P
authors.initials: DP
authors.lastname: Fairlie
mesh_terms: D000818:Animals; D003198:Computer Simulation; D008958:Models, Molecular; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000737:chemistry*
chemical_list: D010456:Peptides, Cyclic