Species selectivity of the Urotensin II receptor: Molecular Modeling study

COMP 46

Soo-Kyung Kim, skkim@wag.caltech.edu, Youyong Li, youyong@gmail.com, Chang Moon Park, Ravi Abrol, and William A. Goddard III, wag@wag.caltech.edu. Materials and Process Simulation Center, California Institute of Technology, 1200 East California Blvd., Beckman Institute (Mail Stop: 139-74) Rm. 054a, Pasadena, CA 91125
Urotensin-II (UT-II) is a disulfide bridged cyclic peptide. UT-II has shown to be the most potent mammalian vasoconstrictor. Thus, a UT-II antagonist could be of therapeutic value in a number of cardiovascular disorders. A novel non-peptidic Urotensin II receptor (UT2R) antagonist, ACT-058362, exhibited marked species selectivity, with >400-fold higher affinities for the human receptors than for rat receptors. In contrast, SB-706375 is a selective antagonist against both human (Kd ~ 9 nM) and rat (Kd ~ 21 nM). To understand the species selectivity of the UT2R, MembStruk and MSCDock were used to predict the UT2R and the binding site. Based on the binding energy, two binding modes with crucial anchoring point constituted by D3.32 were suggested. Various mutations were proposed to further validate the binding site of UR2R. Success of this combined computational and experimental study would help to predict novel preclinical useful UR2R antagonists with high cross-species affinity.