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Similarities between the Binding Sites of SB-206553 at Serotonin Type 2 and Alpha7 Acetylcholine Nicotinic Receptors: Rationale for Its Polypharmacological Profile.

Möller-Acuña P, Contreras-Riquelme JS, Rojas-Fuentes C, Nuñez-Vivanco G, Alzate-Morales J, Iturriaga-Vásquez P, Arias HR, Reyes-Parada M - PLoS ONE (2015)

Bottom Line: To this end, we employed the crystal structures of the 5-HT2BR and acetylcholine binding protein as templates to build homology models of the 5-HT2CR and α7 nAChR, respectively.Our analysis showed that the most plausible binding sites for SB-206553 at 5-HT2Rs and α7 nAChR are remarkably similar, both in size and chemical nature of the amino acid residues lining these pockets, thus providing a rationale to explain its affinity towards both receptor types.Finally, using a computational tool for multiple binding site alignment, we determined a consensus binding site, which should be useful for the rational design of novel compounds acting simultaneously at these two types of highly different protein targets.

View Article: PubMed Central - PubMed

Affiliation: Centro de Bioinformática y Simulación Molecular, Facultad de Ingeniería, Universidad de Talca, 2 Norte 685, Casilla 721, Talca, Chile; Programa de Doctorado en Biotecnología, Universidad de Santiago de Chile, Santiago, Chile.

ABSTRACT
Evidence from systems biology indicates that promiscuous drugs, i.e. those that act simultaneously at various protein targets, are clinically better in terms of efficacy, than those that act in a more selective fashion. This has generated a new trend in drug development called polypharmacology. However, the rational design of promiscuous compounds is a difficult task, particularly when the drugs are aimed to act at receptors with diverse structure, function and endogenous ligand. In the present work, using docking and molecular dynamics methodologies, we established the most probable binding sites of SB-206553, a drug originally described as a competitive antagonist of serotonin type 2B/2C metabotropic receptors (5-HT2B/2CRs) and more recently as a positive allosteric modulator of the ionotropic α7 nicotinic acetylcholine receptor (nAChR). To this end, we employed the crystal structures of the 5-HT2BR and acetylcholine binding protein as templates to build homology models of the 5-HT2CR and α7 nAChR, respectively. Then, using a statistical algorithm, the similarity between these binding sites was determined. Our analysis showed that the most plausible binding sites for SB-206553 at 5-HT2Rs and α7 nAChR are remarkably similar, both in size and chemical nature of the amino acid residues lining these pockets, thus providing a rationale to explain its affinity towards both receptor types. Finally, using a computational tool for multiple binding site alignment, we determined a consensus binding site, which should be useful for the rational design of novel compounds acting simultaneously at these two types of highly different protein targets.

No MeSH data available.


Binding mode of SB-206553 at the extracellular domain of the α7 nAChR.SB-206553 is shown in blue. Main active site amino acid residues (cyan) are rendered as stick models.
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pone.0134444.g008: Binding mode of SB-206553 at the extracellular domain of the α7 nAChR.SB-206553 is shown in blue. Main active site amino acid residues (cyan) are rendered as stick models.

Mentions: As seen in Fig 8, SB-206553 exhibits a binding mode in the α7 nAChR-ECD where the amino group of the carbamate establishes a hydrogen bond with the carbonyl group of Asp133, whereas the pyrroloindole moiety appears located between Phe151 and Phe155, a position that would favor π-stacking interactions between the corresponding aromatic rings. In addition, hydrophobic interactions with Lys138, Leu143, Ala153 and Thr157 were observed, all of which could further stabilize the binding mode of SB-206553 at this site.


Similarities between the Binding Sites of SB-206553 at Serotonin Type 2 and Alpha7 Acetylcholine Nicotinic Receptors: Rationale for Its Polypharmacological Profile.

Möller-Acuña P, Contreras-Riquelme JS, Rojas-Fuentes C, Nuñez-Vivanco G, Alzate-Morales J, Iturriaga-Vásquez P, Arias HR, Reyes-Parada M - PLoS ONE (2015)

Binding mode of SB-206553 at the extracellular domain of the α7 nAChR.SB-206553 is shown in blue. Main active site amino acid residues (cyan) are rendered as stick models.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526571&req=5

pone.0134444.g008: Binding mode of SB-206553 at the extracellular domain of the α7 nAChR.SB-206553 is shown in blue. Main active site amino acid residues (cyan) are rendered as stick models.
Mentions: As seen in Fig 8, SB-206553 exhibits a binding mode in the α7 nAChR-ECD where the amino group of the carbamate establishes a hydrogen bond with the carbonyl group of Asp133, whereas the pyrroloindole moiety appears located between Phe151 and Phe155, a position that would favor π-stacking interactions between the corresponding aromatic rings. In addition, hydrophobic interactions with Lys138, Leu143, Ala153 and Thr157 were observed, all of which could further stabilize the binding mode of SB-206553 at this site.

Bottom Line: To this end, we employed the crystal structures of the 5-HT2BR and acetylcholine binding protein as templates to build homology models of the 5-HT2CR and α7 nAChR, respectively.Our analysis showed that the most plausible binding sites for SB-206553 at 5-HT2Rs and α7 nAChR are remarkably similar, both in size and chemical nature of the amino acid residues lining these pockets, thus providing a rationale to explain its affinity towards both receptor types.Finally, using a computational tool for multiple binding site alignment, we determined a consensus binding site, which should be useful for the rational design of novel compounds acting simultaneously at these two types of highly different protein targets.

View Article: PubMed Central - PubMed

Affiliation: Centro de Bioinformática y Simulación Molecular, Facultad de Ingeniería, Universidad de Talca, 2 Norte 685, Casilla 721, Talca, Chile; Programa de Doctorado en Biotecnología, Universidad de Santiago de Chile, Santiago, Chile.

ABSTRACT
Evidence from systems biology indicates that promiscuous drugs, i.e. those that act simultaneously at various protein targets, are clinically better in terms of efficacy, than those that act in a more selective fashion. This has generated a new trend in drug development called polypharmacology. However, the rational design of promiscuous compounds is a difficult task, particularly when the drugs are aimed to act at receptors with diverse structure, function and endogenous ligand. In the present work, using docking and molecular dynamics methodologies, we established the most probable binding sites of SB-206553, a drug originally described as a competitive antagonist of serotonin type 2B/2C metabotropic receptors (5-HT2B/2CRs) and more recently as a positive allosteric modulator of the ionotropic α7 nicotinic acetylcholine receptor (nAChR). To this end, we employed the crystal structures of the 5-HT2BR and acetylcholine binding protein as templates to build homology models of the 5-HT2CR and α7 nAChR, respectively. Then, using a statistical algorithm, the similarity between these binding sites was determined. Our analysis showed that the most plausible binding sites for SB-206553 at 5-HT2Rs and α7 nAChR are remarkably similar, both in size and chemical nature of the amino acid residues lining these pockets, thus providing a rationale to explain its affinity towards both receptor types. Finally, using a computational tool for multiple binding site alignment, we determined a consensus binding site, which should be useful for the rational design of novel compounds acting simultaneously at these two types of highly different protein targets.

No MeSH data available.