2018
Structural elements required for coupling ion and substrate transport in the neurotransmitter transporter homolog LeuT
Zhang YW, Tavoulari S, Sinning S, Aleksandrova AA, Forrest LR, Rudnick G. Structural elements required for coupling ion and substrate transport in the neurotransmitter transporter homolog LeuT. Proceedings Of The National Academy Of Sciences Of The United States Of America 2018, 115: e8854-e8862. PMID: 30181291, PMCID: PMC6156673, DOI: 10.1073/pnas.1716870115.Peer-Reviewed Original ResearchConceptsTransporter domainConformational changesOpen stateSodium symporter familyIon-substrate couplingTransmembrane ion gradientsSymporter familyNSS transportersSubstrate bindingLeuTIntracellular substratesCysteine accessibilitySubstrate transportAccessibility of substrateTyrosine residuesConformational responseNa2 siteUncoupled movementIon gradientsExtracellular pathwaysMechanistic componentsTransportersProteinTransport of ionsBinding
2015
Two Na+ Sites Control Conformational Change in a Neurotransmitter Transporter Homolog*
Tavoulari S, Margheritis E, Nagarajan A, DeWitt DC, Zhang YW, Rosado E, Ravera S, Rhoades E, Forrest LR, Rudnick G. Two Na+ Sites Control Conformational Change in a Neurotransmitter Transporter Homolog*. Journal Of Biological Chemistry 2015, 291: 1456-1471. PMID: 26582198, PMCID: PMC4714228, DOI: 10.1074/jbc.m115.692012.Peer-Reviewed Original ResearchMeSH KeywordsAmino Acid SubstitutionAmino Acid Transport SystemsAquatic OrganismsBacterial ProteinsBinding SitesCysteineGram-Negative BacteriaLigandsLiposomesModels, MolecularMolecular Dynamics SimulationMutagenesis, Site-DirectedMutationPlasma Membrane Neurotransmitter Transport ProteinsProtein ConformationProtein FoldingProtein StabilityProteolipidsRecombinant ProteinsSodiumConceptsConformational changesTransmembrane helix 1Open conformational stateDependent conformational changesTransporter homologExtracellular gateProkaryotic homologCytoplasmic pathwayHelix 1Interaction networksIntermediary interactionsBiophysical assaysNeurotransmitter transportersSubstrate pathwayNa2 siteConformational statesHelix motionsLeuTDirect interactionDependent closureHomologMutantsDistinct stepsResiduesComputational analysis
2013
How do transporters couple solute movements?
Rudnick G. How do transporters couple solute movements? Molecular Membrane Biology 2013, 30: 355-359. PMID: 24147977, PMCID: PMC4077868, DOI: 10.3109/09687688.2013.842658.Peer-Reviewed Reviews, Practice Guidelines, Standards, and Consensus Statements
2011
Cytoplasmic Permeation Pathway of Neurotransmitter Transporters
Rudnick G. Cytoplasmic Permeation Pathway of Neurotransmitter Transporters. Biochemistry 2011, 50: 7462-7475. PMID: 21774491, PMCID: PMC3164596, DOI: 10.1021/bi200926b.Peer-Reviewed Original ResearchConceptsCytoplasmic permeation pathwaysBacterial amino acid transporter LeuTNeurotransmitter transportersPermeation pathwayKingdoms of lifeMammalian serotonin transporterHigh-resolution crystal structuresFour-helix bundleRecent high-resolution crystal structureSubsequent crystal structureStructural repeatsLeuT structureProtein familyCommon structural featuresSolute transportersRelated proteinsLarge structural familyCytoplasmic oneConformational changesSubstrate siteFirst structureBiological membranesTransportersLeuTExtracellular pathways
2010
Reconstructing a Chloride-binding Site in a Bacterial Neurotransmitter Transporter Homologue*
Tavoulari S, Rizwan AN, Forrest LR, Rudnick G. Reconstructing a Chloride-binding Site in a Bacterial Neurotransmitter Transporter Homologue*. Journal Of Biological Chemistry 2010, 286: 2834-2842. PMID: 21115480, PMCID: PMC3024779, DOI: 10.1074/jbc.m110.186064.Peer-Reviewed Original ResearchConceptsChloride-binding siteConformational changesAdjacent binding sitesSingle point mutationProkaryotic homologuesSubstrate translocationIon-binding sitesTransporter homologueTransport proteinsNeurotransmitter transportersNeurotransmitter transportPoint mutationsBinding sitesHomologuesProteinMutationsCl(-) bindsDirect evidenceTherapeutic drugsSitesDependent formTranslocationTransportersBindsResidues
2008
Mechanism for alternating access in neurotransmitter transporters
Forrest LR, Zhang YW, Jacobs MT, Gesmonde J, Xie L, Honig BH, Rudnick G. Mechanism for alternating access in neurotransmitter transporters. Proceedings Of The National Academy Of Sciences Of The United States Of America 2008, 105: 10338-10343. PMID: 18647834, PMCID: PMC2480614, DOI: 10.1073/pnas.0804659105.Peer-Reviewed Original ResearchConceptsNeurotransmitter transportersMammalian neurotransmitter transportersMammalian serotonin transporterTransmembrane helix 1Bacterial homologueIon-binding sitesTransporter familyExtensive mutagenesisHelix 1Similar repeatsLeuTConformational changesSerotonin transporterRepeatsAlternate conformationConformational differencesExtracellular pathwaysCytoplasmTransportersExtracellular spaceCysteine reagentCrystal structureConformationPathwayAccessibility measurements
2002
Chemical Modification Strategies for Structure‐Function Studies
Rudnick G. Chemical Modification Strategies for Structure‐Function Studies. 2002, 125-141. DOI: 10.1002/0471434043.ch8.ChaptersTransmembrane domainConformational changesPolytopic membrane proteinsStructure-function studiesMembrane proteinsTransporter proteinsReactive residuesLipid bilayersProteinTransportersExternal faceExternal loopChemical modification strategiesDomainChemical modificationSubstrateCysteineResiduesSitesMembraneModificationBilayers
2000
Functional Role of Critical Stripe Residues in Transmembrane Span 7 of the Serotonin Transporter EFFECTS OF Na+, Li+, AND METHANETHIOSULFONATE REAGENTS*
Kamdar G, Penado K, Rudnick G, Stephan M. Functional Role of Critical Stripe Residues in Transmembrane Span 7 of the Serotonin Transporter EFFECTS OF Na+, Li+, AND METHANETHIOSULFONATE REAGENTS*. Journal Of Biological Chemistry 2000, 276: 4038-4045. PMID: 11058600, DOI: 10.1074/jbc.m008483200.Peer-Reviewed Original ResearchConceptsCys-109Methanethiosulfonate reagentsWater-filled poresNative cysteine residuesCysteine-containing mutantsExtracellular loop 1Close-contact regionThree-dimensional structureCysteine residuesTranslocation mechanismControl mutantsAlpha-helixMTSEA-biotinResidue positionsCysteine substitutionsLoop 1Conformational changesMTS reagentsFunctional roleMutantsIon bindingResiduesTransportersIon dependenceSerotonin transporter
1999
The Role of External Loop Regions in Serotonin Transport LOOP SCANNING MUTAGENESIS OF THE SEROTONIN TRANSPORTER EXTERNAL DOMAIN*
Smicun Y, Campbell S, Chen M, Gu H, Rudnick G. The Role of External Loop Regions in Serotonin Transport LOOP SCANNING MUTAGENESIS OF THE SEROTONIN TRANSPORTER EXTERNAL DOMAIN*. Journal Of Biological Chemistry 1999, 274: 36058-36064. PMID: 10593887, DOI: 10.1074/jbc.274.51.36058.Peer-Reviewed Original ResearchConceptsChimeric transportersWild type SERTExternal loop 4High affinity cocaine analogSubsequent conformational changesExternal loop regionsTransmembrane segmentsInitial binding stepScanning mutagenesisWild typeExternal loopLigand bindingSerotonin transporterMutantsConformational changesLoop 4Loop regionConformational flexibilityTransportersCorresponding sequenceBinding stepExternal domainNorepinephrine transporterActivity 5NET substrate
1997
An Extracellular Loop Region of the Serotonin Transporter May Be Involved in the Translocation Mechanism †
Stephan M, Chen M, Penado K, Rudnick G. An Extracellular Loop Region of the Serotonin Transporter May Be Involved in the Translocation Mechanism †. Biochemistry 1997, 36: 1322-1328. PMID: 9063880, DOI: 10.1021/bi962150l.Peer-Reviewed Original ResearchConceptsLarge extracellular loopChimeric transportersWild typeWild type SERTExtracellular loopCocaine analog 2beta-carbomethoxy-3betaCell surface biotinylationWild-type levelsSubstrate translocationExtracellular loop regionSurface biotinylationTranslocation mechanismSerotonin transporterHomologous familyType levelsConformational changesLoop regionRestriction sitesTransportersPoor expressionSubstituted regionsSynaptic cleftDrug bindingSame specificityHigh affinity
1985
Effects of monovalent cations on Semliki Forest virus entry into BHK-21 cells.
Helenius A, Kielian M, Wellsteed J, Mellman I, Rudnick G. Effects of monovalent cations on Semliki Forest virus entry into BHK-21 cells. Journal Of Biological Chemistry 1985, 260: 5691-5697. PMID: 3988769, DOI: 10.1016/s0021-9258(18)89078-0.Peer-Reviewed Original ResearchConceptsSemliki Forest virusEndosome membraneViral envelopeBaby hamster kidney cellsMammalian cellsEndosomal membranesLow endosomalBHK-21 cellsHamster kidney cellsVirus endocytosisIntact cellsConformational changesEndosomesPrelysosomal endosomesViral spike glycoproteinVirus fusionKidney cellsAcidic endosomal pHViral RNAVoltage-sensitive probeEndocytosisVirus entryEndosomal pHCellsSpike glycoprotein