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Mechanism of the Association between Na(+) Binding and Conformations at the Intracellular Gate in Neurotransmitter:Sodium Symporters

Neurotransmitter:sodium symporters (NSSs) terminate neurotransmission by Na(+)-dependent reuptake of released neurotransmitters. Previous studies suggested that Na(+)-binding reconfigures dynamically coupled structural elements in an allosteric interaction network (AIN) responsible for function-rela...

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Autores principales: Stolzenberg, Sebastian, Quick, Matthias, Zhao, Chunfeng, Gotfryd, Kamil, Khelashvili, George, Gether, Ulrik, Loland, Claus J., Javitch, Jonathan A., Noskov, Sergei, Weinstein, Harel, Shi, Lei
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Biochemistry and Molecular Biology 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4447972/
https://www.ncbi.nlm.nih.gov/pubmed/25869126
http://dx.doi.org/10.1074/jbc.M114.625343
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author Stolzenberg, Sebastian
Quick, Matthias
Zhao, Chunfeng
Gotfryd, Kamil
Khelashvili, George
Gether, Ulrik
Loland, Claus J.
Javitch, Jonathan A.
Noskov, Sergei
Weinstein, Harel
Shi, Lei
author_facet Stolzenberg, Sebastian
Quick, Matthias
Zhao, Chunfeng
Gotfryd, Kamil
Khelashvili, George
Gether, Ulrik
Loland, Claus J.
Javitch, Jonathan A.
Noskov, Sergei
Weinstein, Harel
Shi, Lei
author_sort Stolzenberg, Sebastian
collection PubMed
description Neurotransmitter:sodium symporters (NSSs) terminate neurotransmission by Na(+)-dependent reuptake of released neurotransmitters. Previous studies suggested that Na(+)-binding reconfigures dynamically coupled structural elements in an allosteric interaction network (AIN) responsible for function-related conformational changes, but the intramolecular pathway of this mechanism has remained uncharted. We describe a new approach for the modeling and analysis of intramolecular dynamics in the bacterial NSS homolog LeuT. From microsecond-scale molecular dynamics simulations and cognate experimental verifications in both LeuT and human dopamine transporter (hDAT), we apply the novel method to identify the composition and the dynamic properties of their conserved AIN. In LeuT, two different perturbations disrupting Na(+) binding and transport (i.e. replacing Na(+) with Li(+) or the Y268A mutation at the intracellular gate) affect the AIN in strikingly similar ways. In contrast, other mutations that affect the intracellular gate (i.e. R5A and D369A) do not significantly impair Na(+) cooperativity and transport. Our analysis shows these perturbations to have much lesser effects on the AIN, underscoring the sensitivity of this novel method to the mechanistic nature of the perturbation. Notably, this set of observations holds as well for hDAT, where the aligned Y335A, R60A, and D436A mutations also produce different impacts on Na(+) dependence. Thus, the detailed AIN generated from our method is shown to connect Na(+) binding with global conformational changes that are critical for the transport mechanism. That the AIN between the Na(+) binding sites and the intracellular gate in bacterial LeuT resembles that in eukaryotic hDAT highlights the conservation of allosteric pathways underlying NSS function.
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spelling pubmed-44479722015-06-08 Mechanism of the Association between Na(+) Binding and Conformations at the Intracellular Gate in Neurotransmitter:Sodium Symporters Stolzenberg, Sebastian Quick, Matthias Zhao, Chunfeng Gotfryd, Kamil Khelashvili, George Gether, Ulrik Loland, Claus J. Javitch, Jonathan A. Noskov, Sergei Weinstein, Harel Shi, Lei J Biol Chem Molecular Biophysics Neurotransmitter:sodium symporters (NSSs) terminate neurotransmission by Na(+)-dependent reuptake of released neurotransmitters. Previous studies suggested that Na(+)-binding reconfigures dynamically coupled structural elements in an allosteric interaction network (AIN) responsible for function-related conformational changes, but the intramolecular pathway of this mechanism has remained uncharted. We describe a new approach for the modeling and analysis of intramolecular dynamics in the bacterial NSS homolog LeuT. From microsecond-scale molecular dynamics simulations and cognate experimental verifications in both LeuT and human dopamine transporter (hDAT), we apply the novel method to identify the composition and the dynamic properties of their conserved AIN. In LeuT, two different perturbations disrupting Na(+) binding and transport (i.e. replacing Na(+) with Li(+) or the Y268A mutation at the intracellular gate) affect the AIN in strikingly similar ways. In contrast, other mutations that affect the intracellular gate (i.e. R5A and D369A) do not significantly impair Na(+) cooperativity and transport. Our analysis shows these perturbations to have much lesser effects on the AIN, underscoring the sensitivity of this novel method to the mechanistic nature of the perturbation. Notably, this set of observations holds as well for hDAT, where the aligned Y335A, R60A, and D436A mutations also produce different impacts on Na(+) dependence. Thus, the detailed AIN generated from our method is shown to connect Na(+) binding with global conformational changes that are critical for the transport mechanism. That the AIN between the Na(+) binding sites and the intracellular gate in bacterial LeuT resembles that in eukaryotic hDAT highlights the conservation of allosteric pathways underlying NSS function. American Society for Biochemistry and Molecular Biology 2015-05-29 2015-04-13 /pmc/articles/PMC4447972/ /pubmed/25869126 http://dx.doi.org/10.1074/jbc.M114.625343 Text en © 2015 by The American Society for Biochemistry and Molecular Biology, Inc. Author's Choice—Final version free via Creative Commons CC-BY license (http://creativecommons.org/licenses/by/3.0) .
spellingShingle Molecular Biophysics
Stolzenberg, Sebastian
Quick, Matthias
Zhao, Chunfeng
Gotfryd, Kamil
Khelashvili, George
Gether, Ulrik
Loland, Claus J.
Javitch, Jonathan A.
Noskov, Sergei
Weinstein, Harel
Shi, Lei
Mechanism of the Association between Na(+) Binding and Conformations at the Intracellular Gate in Neurotransmitter:Sodium Symporters
title Mechanism of the Association between Na(+) Binding and Conformations at the Intracellular Gate in Neurotransmitter:Sodium Symporters
title_full Mechanism of the Association between Na(+) Binding and Conformations at the Intracellular Gate in Neurotransmitter:Sodium Symporters
title_fullStr Mechanism of the Association between Na(+) Binding and Conformations at the Intracellular Gate in Neurotransmitter:Sodium Symporters
title_full_unstemmed Mechanism of the Association between Na(+) Binding and Conformations at the Intracellular Gate in Neurotransmitter:Sodium Symporters
title_short Mechanism of the Association between Na(+) Binding and Conformations at the Intracellular Gate in Neurotransmitter:Sodium Symporters
title_sort mechanism of the association between na(+) binding and conformations at the intracellular gate in neurotransmitter:sodium symporters
topic Molecular Biophysics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4447972/
https://www.ncbi.nlm.nih.gov/pubmed/25869126
http://dx.doi.org/10.1074/jbc.M114.625343
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