Alwassil OI, Abdrakhmanova GR, Dukat M. Computational analysis of non-competitive antagonist arylguanidine-α7 nAChR complexes.
J Mol Graph Model 2021;
107:107943. [PMID:
34058639 DOI:
10.1016/j.jmgm.2021.107943]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 04/07/2021] [Accepted: 05/11/2021] [Indexed: 10/21/2022]
Abstract
meta-Chlorophenylguanidine (1) is a non-competitive α7 nicotinic acetylcholine receptor (nAChR) antagonist. Here we examined the hydrogen bond donor role of the anilinic N1-H on the inhibitory effect of 1 by preparing its N1-CH3 counterpart 2. Analog 2 was found to be at least as potent as 1 as a non-competitive α7 nAChR antagonist in a patch-clamp assay. To establish a structural basis for the mode of interaction of guanidines 1 and 2, we generated 100 homology models of the hα7 nAChR. This was followed by Connolly surface (SYBYL-X2.1) and blind docking (AutoDock 4.1) studies to identify eight possible binding pockets, two of which were supported by empirical data and employed in our docking studies. The optimized model-ligand complexes were analyzed using a Hydropathic INTeractions (HINT) analysis in order to compare and contrast different binding pockets and modes. We identified a potential allosteric binding site and distinct rotameric binding modes for 1 and 2 at α7 nAChRs. These differences in the binding orientations minimized the importance of an anilinic NH function for the antagonist activity at nACh receptors.
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