Identification of binding sites of prazosin, tamsulosin and KMD-3213 with alpha(1)-adrenergic receptor subtypes by molecular modeling.

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Ishiguro M, Futabayashi Y, Ohnuki T, Ahmed M, Muramatsu I, Nagatomo T

Identification of binding sites of prazosin, tamsulosin and KMD-3213 with alpha(1)-adrenergic receptor subtypes by molecular modeling.

Life Sci. 2002 Oct 11;71(21):2531-41.

PubMed ID

12270758 [ View in PubMed

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Abstract

This investigation was performed to assess the importance of interaction in the bindings of selective and nonselective alpha(1)-antagonists to alpha(1)-adrenergic receptor (alpha(1)-AR) subtypes using molecular modeling. The alpha(1)-antagonists used in this study were prazosin, tamsulosin and KMD-3213. Molecular modeling was performed on Octane 2 workstation (Silicon Graphics) using Discover/Insight II software (Molecular Simulations Inc.). Through molecular modeling, possible binding sites for these drugs were suggested to lie between transmembrane domains (TM) 3, 4, 5 and 6 of the alpha(1)-AR subtypes. In prazosin, the 4-amino group, 1-nitrogen atom and two methoxy groups of quinazoline ring possibly interact with the amino acids in TM3, TM5 and TM6 of alpha(1)-ARs. In tamsulosin, amine group of ethanyl amine chain, methoxy group of benzene ring and sulfonamide nitrogen of benzene ring interacts in TM3, TM4 and TM5 of alpha(1)-ARs. In KMD-3213, amine of ethyl amine chain and indoline nitrogen of this compound possibly interact within TM3 and TM5 of alpha(1)-ARs. Amide nitrogen of KMD-3213 also interacts within TM4 of alpha(1A)-AR. The results of the present study suggested that prazosin has similar binding sites in all the alpha(1)-AR subtypes while tamsulosin interacts at higher number of sites with alpha(1D)-subtype than other alpha(1)-AR subtypes. KMD-3213 being an alpha(1A)-AR selective ligand, binds to higher number of sites of alpha(1A) subtype than to other subtypes. All these amino acids are located near the extracellular loop. These findings are consistent with the previous studies that antagonists bind higher in the pocket closer to the extracellular surface unlike agonist binding.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Tamsulosin	Alpha-1B adrenergic receptor	Protein	Humans	Unknown	Antagonist	Details
Tamsulosin	Alpha-1D adrenergic receptor	Protein	Humans	Unknown	Antagonist	Details