Mutational mapping and modeling of the binding site for (S)-citalopram in the human serotonin transporter

Jacob Andersen; Lars Olsen; Kasper Bø Hansen; Olivier Taboureau; Flemming Steen Jørgensen; Anne Marie Jørgensen; Benny Bang-Andersen; Jan Egebjerg; Kristian Strømgaard; Anders Skov Kristensen

doi:10.1074/jbc.M109.072587

Mutational mapping and modeling of the binding site for (S)-citalopram in the human serotonin transporter

Jacob Andersen, Lars Olsen, Kasper Bø Hansen, Olivier Taboureau, Flemming Steen Jørgensen, Anne Marie Jørgensen, Benny Bang-Andersen, Jan Egebjerg, Kristian Strømgaard, Anders Skov Kristensen

76 Citations (Scopus)

Abstract

The serotonin transporter (SERT) regulates extracellular levels of the neurotransmitter serotonin (5-hydroxytryptamine) in the brain by facilitating uptake of released 5-hydroxytryptamine into neuronal cells. SERT is the target for widely used antidepressant drugs, including imipramine, fluoxetine, and (S)-citalopram, which are competitive inhibitors of the transport function. Knowledge of the molecular details of the antidepressant binding sites in SERT has been limited due to lack of structural data on SERT. Here, we present a characterization of the (S)-citalopram binding pocket in human SERT (hSERT) using mutational and computational approaches. Comparative modeling and ligand docking reveal that (S)-citalopram fits into the hSERT substrate binding pocket, where (S)-citalopram can adopt a number of different binding orientations. We find, however, that only one of these binding modes is functionally relevant from studying the effects of 64 point mutations around the putative substrate binding site. The mutational mapping also identify novel hSERT residues that are crucial for (S)-citalopram binding. The model defines the molecular determinants for (S)-citalopram binding to hSERT and demonstrates that the antidepressant binding site overlaps with the substrate binding site.

Original language	English
Journal	Journal of Biological Chemistry
Volume	285
Issue number	3
Pages (from-to)	2051-2063
ISSN	0021-9258
DOIs	https://doi.org/10.1074/jbc.M109.072587
Publication status	Published - 15 Jan 2010

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Former Faculty of Pharmaceutical Sciences

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10.1074/jbc.M109.072587

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@article{935976700f2311df825d000ea68e967b,

title = "Mutational mapping and modeling of the binding site for (S)-citalopram in the human serotonin transporter",

abstract = "The serotonin transporter (SERT) regulates extracellular levels of the neurotransmitter serotonin (5-hydroxytryptamine) in the brain by facilitating uptake of released 5-hydroxytryptamine into neuronal cells. SERT is the target for widely used antidepressant drugs, including imipramine, fluoxetine, and (S)-citalopram, which are competitive inhibitors of the transport function. Knowledge of the molecular details of the antidepressant binding sites in SERT has been limited due to lack of structural data on SERT. Here, we present a characterization of the (S)-citalopram binding pocket in human SERT (hSERT) using mutational and computational approaches. Comparative modeling and ligand docking reveal that (S)-citalopram fits into the hSERT substrate binding pocket, where (S)-citalopram can adopt a number of different binding orientations. We find, however, that only one of these binding modes is functionally relevant from studying the effects of 64 point mutations around the putative substrate binding site. The mutational mapping also identify novel hSERT residues that are crucial for (S)-citalopram binding. The model defines the molecular determinants for (S)-citalopram binding to hSERT and demonstrates that the antidepressant binding site overlaps with the substrate binding site.",

keywords = "Former Faculty of Pharmaceutical Sciences",

author = "Jacob Andersen and Lars Olsen and Hansen, {Kasper B{\o}} and Olivier Taboureau and J{\o}rgensen, {Flemming Steen} and J{\o}rgensen, {Anne Marie} and Benny Bang-Andersen and Jan Egebjerg and Kristian Str{\o}mgaard and Kristensen, {Anders Skov}",

note = "Kasper B{\o} Hansen er ogs{\aa} tilknyttet: Emory University School of Medicine, Atlanta, USA",

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doi = "10.1074/jbc.M109.072587",

language = "English",

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T1 - Mutational mapping and modeling of the binding site for (S)-citalopram in the human serotonin transporter

AU - Andersen, Jacob

AU - Olsen, Lars

AU - Hansen, Kasper Bø

AU - Taboureau, Olivier

AU - Jørgensen, Flemming Steen

AU - Jørgensen, Anne Marie

AU - Bang-Andersen, Benny

AU - Egebjerg, Jan

AU - Strømgaard, Kristian

AU - Kristensen, Anders Skov

N1 - Kasper Bø Hansen er også tilknyttet: Emory University School of Medicine, Atlanta, USA

PY - 2010/1/15

Y1 - 2010/1/15

N2 - The serotonin transporter (SERT) regulates extracellular levels of the neurotransmitter serotonin (5-hydroxytryptamine) in the brain by facilitating uptake of released 5-hydroxytryptamine into neuronal cells. SERT is the target for widely used antidepressant drugs, including imipramine, fluoxetine, and (S)-citalopram, which are competitive inhibitors of the transport function. Knowledge of the molecular details of the antidepressant binding sites in SERT has been limited due to lack of structural data on SERT. Here, we present a characterization of the (S)-citalopram binding pocket in human SERT (hSERT) using mutational and computational approaches. Comparative modeling and ligand docking reveal that (S)-citalopram fits into the hSERT substrate binding pocket, where (S)-citalopram can adopt a number of different binding orientations. We find, however, that only one of these binding modes is functionally relevant from studying the effects of 64 point mutations around the putative substrate binding site. The mutational mapping also identify novel hSERT residues that are crucial for (S)-citalopram binding. The model defines the molecular determinants for (S)-citalopram binding to hSERT and demonstrates that the antidepressant binding site overlaps with the substrate binding site.

AB - The serotonin transporter (SERT) regulates extracellular levels of the neurotransmitter serotonin (5-hydroxytryptamine) in the brain by facilitating uptake of released 5-hydroxytryptamine into neuronal cells. SERT is the target for widely used antidepressant drugs, including imipramine, fluoxetine, and (S)-citalopram, which are competitive inhibitors of the transport function. Knowledge of the molecular details of the antidepressant binding sites in SERT has been limited due to lack of structural data on SERT. Here, we present a characterization of the (S)-citalopram binding pocket in human SERT (hSERT) using mutational and computational approaches. Comparative modeling and ligand docking reveal that (S)-citalopram fits into the hSERT substrate binding pocket, where (S)-citalopram can adopt a number of different binding orientations. We find, however, that only one of these binding modes is functionally relevant from studying the effects of 64 point mutations around the putative substrate binding site. The mutational mapping also identify novel hSERT residues that are crucial for (S)-citalopram binding. The model defines the molecular determinants for (S)-citalopram binding to hSERT and demonstrates that the antidepressant binding site overlaps with the substrate binding site.

KW - Former Faculty of Pharmaceutical Sciences

U2 - 10.1074/jbc.M109.072587

DO - 10.1074/jbc.M109.072587

M3 - Journal article

C2 - 19892699

SN - 0021-9258

VL - 285

SP - 2051

EP - 2063

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 3

ER -

Mutational mapping and modeling of the binding site for (S)-citalopram in the human serotonin transporter

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