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Zhou W, Trinco G, Slotboom DJ, Forrest LR, Faraldo-Gómez JD. On the Role of a Conserved Methionine in the Na +-Coupling Mechanism of a Neurotransmitter Transporter Homolog. Neurochem Res 2021; 47:163-175. [PMID: 33565025 PMCID: PMC8431971 DOI: 10.1007/s11064-021-03253-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/17/2021] [Accepted: 01/19/2021] [Indexed: 11/26/2022]
Abstract
Excitatory amino acid transporters (EAAT) play a key role in glutamatergic synaptic communication. Driven by transmembrane cation gradients, these transporters catalyze the reuptake of glutamate from the synaptic cleft once this neurotransmitter has been utilized for signaling. Two decades ago, pioneering studies in the Kanner lab identified a conserved methionine within the transmembrane domain as key for substrate turnover rate and specificity; later structural work, particularly for the prokaryotic homologs GltPh and GltTk, revealed that this methionine is involved in the coordination of one of the three Na+ ions that are co-transported with the substrate. Albeit extremely atypical, the existence of this interaction is consistent with biophysical analyses of GltPh showing that mutations of this methionine diminish the binding cooperativity between substrates and Na+. It has been unclear, however, whether this intriguing methionine influences the thermodynamics of the transport reaction, i.e., its substrate:ion stoichiometry, or whether it simply fosters a specific kinetics in the binding reaction, which, while influential for the turnover rate, do not fundamentally explain the ion-coupling mechanism of this class of transporters. Here, studies of GltTk using experimental and computational methods independently arrive at the conclusion that the latter hypothesis is the most plausible, and lay the groundwork for future efforts to uncover the underlying mechanism.
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Affiliation(s)
- Wenchang Zhou
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Gianluca Trinco
- Groningen Biomolecular Sciences and Biotechnology Institute, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Dirk J Slotboom
- Groningen Biomolecular Sciences and Biotechnology Institute, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands.
| | - Lucy R Forrest
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - José D Faraldo-Gómez
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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Arkhipova V, Fu H, Hoorens MWH, Trinco G, Lameijer LN, Marin E, Feringa BL, Poelarends GJ, Szymanski W, Slotboom DJ, Guskov A. Structural Aspects of Photopharmacology: Insight into the Binding of Photoswitchable and Photocaged Inhibitors to the Glutamate Transporter Homologue. J Am Chem Soc 2021; 143:1513-1520. [PMID: 33449695 PMCID: PMC7844824 DOI: 10.1021/jacs.0c11336] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
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Photopharmacology addresses the challenge of drug selectivity and
side effects through creation of photoresponsive molecules activated
with light with high spatiotemporal precision. This is achieved through
incorporation of molecular photoswitches and photocages into the pharmacophore.
However, the structural basis for the light-induced modulation of
inhibitory potency in general is still missing, which poses a major
design challenge for this emerging field of research. Here we solved
crystal structures of the glutamate transporter homologue GltTk in complex with photoresponsive transport inhibitors—azobenzene
derivative of TBOA (both in trans and cis configuration) and with the photocaged compound ONB-hydroxyaspartate.
The essential role of glutamate transporters in the functioning of
the central nervous system renders them potential therapeutic targets
in the treatment of neurodegenerative diseases. The obtained structures
provide a clear structural insight into the origins of photocontrol
in photopharmacology and lay the foundation for application of photocontrolled
ligands to study the transporter dynamics by using time-resolved X-ray
crystallography.
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Affiliation(s)
- Valentina Arkhipova
- University Medical Center Groningen, Department of Radiology, Medical Imaging Center, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.,Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Haigen Fu
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Mark W H Hoorens
- University Medical Center Groningen, Department of Radiology, Medical Imaging Center, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.,Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Gianluca Trinco
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Lucien N Lameijer
- University Medical Center Groningen, Department of Radiology, Medical Imaging Center, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.,Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Egor Marin
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.,Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Ben L Feringa
- Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Gerrit J Poelarends
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Wiktor Szymanski
- University Medical Center Groningen, Department of Radiology, Medical Imaging Center, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.,Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Dirk J Slotboom
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Albert Guskov
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.,Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
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Arkhipova V, Trinco G, Ettema TW, Jensen S, Slotboom DJ, Guskov A. Binding and transport of D-aspartate by the glutamate transporter homolog Glt Tk. eLife 2019; 8:45286. [PMID: 30969168 PMCID: PMC6482001 DOI: 10.7554/elife.45286] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/09/2019] [Indexed: 01/31/2023] Open
Abstract
Mammalian glutamate transporters are crucial players in neuronal communication as they perform neurotransmitter reuptake from the synaptic cleft. Besides L-glutamate and L-aspartate, they also recognize D-aspartate, which might participate in mammalian neurotransmission and/or neuromodulation. Much of the mechanistic insight in glutamate transport comes from studies of the archeal homologs GltPh from Pyrococcus horikoshii and GltTk from Thermococcus kodakarensis. Here, we show that GltTk transports D-aspartate with identical Na+: substrate coupling stoichiometry as L-aspartate, and that the affinities (Kd and Km) for the two substrates are similar. We determined a crystal structure of GltTk with bound D-aspartate at 2.8 Å resolution. Comparison of the L- and D-aspartate bound GltTk structures revealed that D-aspartate is accommodated with only minor rearrangements in the structure of the binding site. The structure explains how the geometrically different molecules L- and D-aspartate are recognized and transported by the protein in the same way.
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Affiliation(s)
- Valentina Arkhipova
- Groningen Biomolecular Sciences and Biotechnology Institute, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Gianluca Trinco
- Groningen Biomolecular Sciences and Biotechnology Institute, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Thijs W Ettema
- Groningen Biomolecular Sciences and Biotechnology Institute, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Sonja Jensen
- Groningen Biomolecular Sciences and Biotechnology Institute, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Dirk J Slotboom
- Groningen Biomolecular Sciences and Biotechnology Institute, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Albert Guskov
- Groningen Biomolecular Sciences and Biotechnology Institute, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
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Kuipers G, Karyolaimos A, Zhang Z, Ismail N, Trinco G, Vikström D, Slotboom DJ, de Gier JW. The tunable pReX expression vector enables optimizing the T7-based production of membrane and secretory proteins in E. coli. Microb Cell Fact 2017; 16:226. [PMID: 29246156 PMCID: PMC5732464 DOI: 10.1186/s12934-017-0840-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/05/2017] [Indexed: 11/16/2022] Open
Abstract
Background To optimize the production of membrane and secretory proteins in Escherichia coli, it is critical to harmonize the expression rates of the genes encoding these proteins with the capacity of their biogenesis machineries. Therefore, we engineered the Lemo21(DE3) strain, which is derived from the T7 RNA polymerase-based BL21(DE3) protein production strain. In Lemo21(DE3), the T7 RNA polymerase activity can be modulated by the controlled co-production of its natural inhibitor T7 lysozyme. This setup enables to precisely tune target gene expression rates in Lemo21(DE3). The t7lys gene is expressed from the pLemo plasmid using the titratable rhamnose promoter. A disadvantage of the Lemo21(DE3) setup is that the system is based on two plasmids, a T7 expression vector and pLemo. The aim of this study was to simplify the Lemo21(DE3) setup by incorporating the key elements of pLemo in a standard T7-based expression vector. Results By incorporating the gene encoding the T7 lysozyme under control of the rhamnose promoter in a standard T7-based expression vector, pReX was created (ReX stands for Regulated gene eXpression). For two model membrane proteins and a model secretory protein we show that the optimized production yields obtained with the pReX expression vector in BL21(DE3) are similar to the ones obtained with Lemo21(DE3) using a standard T7 expression vector. For another secretory protein, a c-type cytochrome, we show that pReX, in contrast to Lemo21(DE3), enables the use of a helper plasmid that is required for the maturation and hence the production of this heme c protein. Conclusions Here, we created pReX, a T7-based expression vector that contains the gene encoding the T7 lysozyme under control of the rhamnose promoter. pReX enables regulated T7-based target gene expression using only one plasmid. We show that with pReX the production of membrane and secretory proteins can be readily optimized. Importantly, pReX facilitates the use of helper plasmids. Furthermore, the use of pReX is not restricted to BL21(DE3), but it can in principle be used in any T7 RNAP-based strain. Thus, pReX is a versatile alternative to Lemo21(DE3). Electronic supplementary material The online version of this article (10.1186/s12934-017-0840-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Grietje Kuipers
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91, Stockholm, Sweden.,Xbrane Biopharma AB, SE-111 45, Stockholm, Sweden
| | - Alexandros Karyolaimos
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Zhe Zhang
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91, Stockholm, Sweden
| | | | - Gianluca Trinco
- University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, NL-9747 AG, Groningen, The Netherlands
| | | | - Dirk Jan Slotboom
- University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, NL-9747 AG, Groningen, The Netherlands
| | - Jan-Willem de Gier
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91, Stockholm, Sweden.
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Nardoni A, Di Piazza V, Moretti V, Copetti R, Trinco G. [Is serotonin implicated in the pathogenesis of the alcohol abstinence syndrome?]. Minerva Med 1989; 80:281-3. [PMID: 2469992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
5-Hydroxyindoleacetic acid (5-HIAA), the main metabolite of 5-hydroxytryptamine or serotonin, excreted in the urine over a 24 hour period was systematically measured in 35 patients with alcohol withdrawal syndrome (AWS). The level of excreted urinary 5-HIAA ac. was high in only a few patients. The pathogenic mechanisms involved are discussed and though the role of serotonin in the pathogenesis of AWS seems of secondary importance, some 5-hydroxytryptamine methyl analogues may have a major role in the pathogenesis of hallucinations caused by alcohol withdrawal.
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Affiliation(s)
- A Nardoni
- Divisione di Medicina Generale, Ospedale S. Antonio, Tolmezzo (Udine)
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Nardoni A, di Piazza V, Moretti V, Copetti R, Trinco G, Geatti O. [False values of blood digoxin in patients with acute and chronic liver disease. Role of canrenoate potassium and comparison of radioimmunologic and immunoenzymatic methods]. Clin Ter 1988; 125:287-90. [PMID: 2974364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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