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==Crystal structure analysis of LeuT complexed with L-alanine, sodium, and clomipramine== | |||
<StructureSection load='2qei' size='340' side='right'caption='[[2qei]], [[Resolution|resolution]] 1.85Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[2qei]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Aquifex_aeolicus_VF5 Aquifex aeolicus VF5]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2QEI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2QEI FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.85Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ALA:ALANINE'>ALA</scene>, <scene name='pdbligand=BOG:B-OCTYLGLUCOSIDE'>BOG</scene>, <scene name='pdbligand=CXX:3-(3-CHLORO-5H-DIBENZO[B,F]AZEPIN-5-YL)-N,N-DIMETHYLPROPAN-1-AMINE'>CXX</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2qei FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2qei OCA], [https://pdbe.org/2qei PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2qei RCSB], [https://www.ebi.ac.uk/pdbsum/2qei PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2qei ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/O67854_AQUAE O67854_AQUAE] | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/qe/2qei_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2qei ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Sodium-coupled transporters are ubiquitous pumps that harness pre-existing sodium gradients to catalyse the thermodynamically unfavourable uptake of essential nutrients, neurotransmitters and inorganic ions across the lipid bilayer. Dysfunction of these integral membrane proteins has been implicated in glucose/galactose malabsorption, congenital hypothyroidism, Bartter's syndrome, epilepsy, depression, autism and obsessive-compulsive disorder. Sodium-coupled transporters are blocked by a number of therapeutically important compounds, including diuretics, anticonvulsants and antidepressants, many of which have also become indispensable tools in biochemical experiments designed to probe antagonist binding sites and to elucidate transport mechanisms. Steady-state kinetic data have revealed that both competitive and noncompetitive modes of inhibition exist. Antagonist dissociation experiments on the serotonin transporter (SERT) have also unveiled the existence of a low-affinity allosteric site that slows the dissociation of inhibitors from a separate high-affinity site. Despite these strides, atomic-level insights into inhibitor action have remained elusive. Here we screen a panel of molecules for their ability to inhibit LeuT, a prokaryotic homologue of mammalian neurotransmitter sodium symporters, and show that the tricyclic antidepressant (TCA) clomipramine noncompetitively inhibits substrate uptake. Cocrystal structures show that clomipramine, along with two other TCAs, binds in an extracellular-facing vestibule about 11 A above the substrate and two sodium ions, apparently stabilizing the extracellular gate in a closed conformation. Off-rate assays establish that clomipramine reduces the rate at which leucine dissociates from LeuT and reinforce our contention that this TCA inhibits LeuT by slowing substrate release. Our results represent a molecular view into noncompetitive inhibition of a sodium-coupled transporter and define principles for the rational design of new inhibitors. | |||
Antidepressant binding site in a bacterial homologue of neurotransmitter transporters.,Singh SK, Yamashita A, Gouaux E Nature. 2007 Aug 23;448(7156):952-6. Epub 2007 Aug 8. PMID:17687333<ref>PMID:17687333</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 2qei" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Leucine transporter|Leucine transporter]] | |||
*[[Symporter 3D structures|Symporter 3D structures]] | |||
[[ | == References == | ||
[[ | <references/> | ||
__TOC__ | |||
</StructureSection> | |||
[[Category: Aquifex aeolicus VF5]] | |||
[[Category: Large Structures]] | |||
[[Category: | [[Category: Gouaux E]] | ||
[[Category: | [[Category: Singh SK]] | ||
[[Category: | [[Category: Yamashita A]] | ||
[[Category: | |||
[[Category: | |||
Latest revision as of 14:29, 30 August 2023
Crystal structure analysis of LeuT complexed with L-alanine, sodium, and clomipramineCrystal structure analysis of LeuT complexed with L-alanine, sodium, and clomipramine
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSodium-coupled transporters are ubiquitous pumps that harness pre-existing sodium gradients to catalyse the thermodynamically unfavourable uptake of essential nutrients, neurotransmitters and inorganic ions across the lipid bilayer. Dysfunction of these integral membrane proteins has been implicated in glucose/galactose malabsorption, congenital hypothyroidism, Bartter's syndrome, epilepsy, depression, autism and obsessive-compulsive disorder. Sodium-coupled transporters are blocked by a number of therapeutically important compounds, including diuretics, anticonvulsants and antidepressants, many of which have also become indispensable tools in biochemical experiments designed to probe antagonist binding sites and to elucidate transport mechanisms. Steady-state kinetic data have revealed that both competitive and noncompetitive modes of inhibition exist. Antagonist dissociation experiments on the serotonin transporter (SERT) have also unveiled the existence of a low-affinity allosteric site that slows the dissociation of inhibitors from a separate high-affinity site. Despite these strides, atomic-level insights into inhibitor action have remained elusive. Here we screen a panel of molecules for their ability to inhibit LeuT, a prokaryotic homologue of mammalian neurotransmitter sodium symporters, and show that the tricyclic antidepressant (TCA) clomipramine noncompetitively inhibits substrate uptake. Cocrystal structures show that clomipramine, along with two other TCAs, binds in an extracellular-facing vestibule about 11 A above the substrate and two sodium ions, apparently stabilizing the extracellular gate in a closed conformation. Off-rate assays establish that clomipramine reduces the rate at which leucine dissociates from LeuT and reinforce our contention that this TCA inhibits LeuT by slowing substrate release. Our results represent a molecular view into noncompetitive inhibition of a sodium-coupled transporter and define principles for the rational design of new inhibitors. Antidepressant binding site in a bacterial homologue of neurotransmitter transporters.,Singh SK, Yamashita A, Gouaux E Nature. 2007 Aug 23;448(7156):952-6. Epub 2007 Aug 8. PMID:17687333[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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