"The" allosteric site? The one studied to date, in any event. Could be a very important reagent....
J Med Chem. 2015 Nov 28. [Epub ahead of print]
Novel Electrophilic and Photoaffinity Covalent Probes for Mapping the Cannabinoid 1 Receptor Allosteric Site(s).
Kulkarni PM, Kulkarni AR, Korde A, Tichkule RB, Laprairie RB1, Denovan-Wright EM1, Zhou H, Janero DR, Zvonok N, Makriyannis A, Cascio MG2, Pertwee RG2, Thakur GA.
1Department of Pharmacology, Dalhousie University , Halifax NS Canada B3H 4R2.2School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen , Foresterhill, Aberdeen, AB25 2ZD, Scotland.
Undesirable side effects associated with orthosteric agonists/antagonists of cannabinoid 1 receptor (CB1R), a tractable target for treating several pathologies affecting humans, have greatly limited their translational potential. Recent discovery of CB1R negative allosteric modulators (NAMs) has renewed interest in CB1R by offering a potentially safer therapeutic avenue. To elucidate the CB1R allosteric binding motif and thereby facilitate rational drug discovery, we report the synthesis and biochemical characterization of first covalent ligands designed to bind irreversibly to the CB1Rallosteric site. Either an electrophilic or a photoactivatable group was introduced at key positions of two classical CB1R NAMs: Org27569 (1) and PSNCBAM-1 (2). Among these, 20 (GAT100) emerged as the most potent NAM in functional assays, did not exhibit inverse agonism, and behaved as a robust positive allosteric modulator of binding of orthosteric agonist CP55,940. This novel covalent probe can serve as a useful tool for characterizing CB1R allosteric ligand-binding motifs. |
