American Chemical Society
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χ‑Space Screening of Dermorphin-Based Tetrapeptides through Use of Constrained Arylazepinone and Quinolinone Scaffolds

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journal contribution
posted on 2017-10-04, 00:00 authored by Olivier Van der Poorten, Robin Van Den Hauwe, Emilie Eiselt, Cecilia Betti, Karel Guillemyn, Nga N. Chung, François Hallé, Frédéric Bihel, Peter W. Schiller, Dirk Tourwé, Philippe Sarret, Louis Gendron, Steven Ballet
Herein, the synthesis of novel conformationally constrained amino acids, 4-amino-8-bromo-2-benzazepin-3-one (8-Br-Aba), 3-amino-3,4-dihydroquinolin-2-one, and regioisomeric 4-amino-naphthoazepinones (1- and 2-Ana), is described. Introduction of these constricted scaffolds into the N-terminal tetrapeptide of dermorphin (i.e., H-Tyr-d-Ala-Phe-Gly-NH2) induced significant shifts in binding affinity, selectivity, and in vitro activity at the μ- and δ-opioid receptors (MOP and DOP, respectively). A reported constrained μ-/δ-opioid lead tetrapeptide H-Dmt-d-Arg-Aba-Gly-NH2 was modified through application of various constrained building blocks to identify optimal spatial orientations in view of activity at the opioid receptors. Interestingly, when the aromatic moieties were turned toward the C-terminus of the peptide sequences, (partial) (ant)­agonism at MOP and weak (ant)­agonism at DOP were noticed, whereas the incorporation of the 1-Ana residue led toward balanced low nanomolar MOP/DOP binding and in vitro agonism.