Ligand selectivity for the acetylcholine binding site of the rat alpha4beta2 and alpha3beta4 nicotinic subtypes investigated by molecular docking

J Med Chem. 2005 Aug 11;48(16):5123-30. doi: 10.1021/jm040881a.

Abstract

The homology models of the extracellular domains of the neuronal alpha4beta2 (pdb code: 1ole) and ganglionic alpha3beta4 (pdb code: 1olf) rat nicotinic acetylcholine receptor (nAChR) subtypes were refined and energetically minimized. In this work, a series of nAChR ligands (1-15) were docked into the modeled binding cavity of both receptors. High-affinity, toxic ligands such as epibatidine (1) and dechloroepibatidine (2) docked into cluster 1 with the charged tertiary amino group, forming a pi-cation interaction with Trp 147 on the (+) side of the alpha4 subunit and establishing a characteristic H-bond with the Lys 77 on the (-) side of the beta2 subunit. The nontoxic ligands such as 33bMet (3), (S)-A-85380 (4), and acetylcholine (6) docked into cluster 2 with the same pi-cation interaction but with the rest of the molecule occupying a different moiety of the binding pocket. Molecular docking into the alpha3beta4 subtype showed that both enantiomers of 1 (1a and 1b) are representative templates for ligands with affinity toward this ganglionic nAChR subtype. The ranking scores of the docked molecules confirm the existence of structure-dependent subtype selectivity and shed light on the design of specific and selective alpha4beta2 nAChR subtype ligands.

MeSH terms

  • Acetylcholine / chemistry*
  • Acetylcholine / metabolism
  • Animals
  • Azetidines / chemistry
  • Binding Sites
  • Binding, Competitive
  • Brain / metabolism
  • Bridged Bicyclo Compounds, Heterocyclic / chemistry
  • Bridged Bicyclo Compounds, Heterocyclic / metabolism
  • Bridged Bicyclo Compounds, Heterocyclic / toxicity
  • Cell Line
  • Crystallography, X-Ray
  • Hydrogen Bonding
  • In Vitro Techniques
  • Isoxazoles / chemistry
  • Ligands
  • Mice
  • Models, Molecular
  • Nerve Tissue Proteins / chemistry*
  • Nerve Tissue Proteins / metabolism
  • Oocytes / metabolism
  • Pyridines / chemistry
  • Pyridines / metabolism
  • Pyridines / toxicity
  • Pyrrolidines / chemistry
  • Rats
  • Receptors, Nicotinic / chemistry*
  • Receptors, Nicotinic / metabolism
  • Snails
  • Stereoisomerism
  • Thermodynamics
  • Xenopus

Substances

  • 3-(2-(pyrrolidinyl)methoxy)pyridine
  • A 85380
  • Azetidines
  • Bridged Bicyclo Compounds, Heterocyclic
  • Isoxazoles
  • Ligands
  • Nerve Tissue Proteins
  • Pyridines
  • Pyrrolidines
  • Receptors, Nicotinic
  • nicotinic receptor alpha3beta4
  • nicotinic receptor alpha4beta2
  • 3-methyl-5-(1-methyl-2-pyrrolidinyl)isoxazole
  • epibatidine
  • Acetylcholine