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Dumazer A, Gómez-Santacana X, Malhaire F, Jopling C, Maurel D, Lebon G, Llebaria A, Goudet C. Optical Control of Adenosine A 2A Receptor Using Istradefylline Photosensitivity. ACS Chem Neurosci 2024; 15:645-655. [PMID: 38275568 DOI: 10.1021/acschemneuro.3c00721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024] Open
Abstract
In recent years, there has been growing interest in the potential therapeutic use of inhibitors of adenosine A2A receptors (A2AR) for the treatment of neurodegenerative diseases and cancer. Nevertheless, the widespread expression of A2AR throughout the body emphasizes the importance of temporally and spatially selective ligands. Photopharmacology is an emerging strategy that utilizes photosensitive ligands to attain high spatiotemporal precision and regulate the function of biomolecules using light. In this study, we combined photochemistry and cellular and in vivo photopharmacology to investigate the light sensitivity of the FDA-approved antagonist istradefylline and its potential use as an A2AR photopharmacological tool. Our findings reveal that istradefylline exhibits rapid trans-to-cis isomerization under near-UV light, and prolonged exposure results in the formation of photocycloaddition products. We demonstrate that exposure to UV light triggers a time-dependent decrease in the antagonistic activity of istradefylline in A2AR-expressing cells and enables real-time optical control of A2AR signaling in living cells and zebrafish. Together, these data demonstrate that istradefylline is a photoinactivatable A2AR antagonist and that this property can be utilized to perform photopharmacological experiments in living cells and animals.
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Affiliation(s)
- Anaëlle Dumazer
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
- MCS, Laboratory of Medicinal Chemistry and Synthesis, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain
| | - Xavier Gómez-Santacana
- MCS, Laboratory of Medicinal Chemistry and Synthesis, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain
| | - Fanny Malhaire
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Chris Jopling
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Damien Maurel
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Guillaume Lebon
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Amadeu Llebaria
- MCS, Laboratory of Medicinal Chemistry and Synthesis, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain
| | - Cyril Goudet
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
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2
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Lebon G. Steering G protein activation by mGlu heterodimer. Cell Res 2023; 33:735-736. [PMID: 37402897 PMCID: PMC10542342 DOI: 10.1038/s41422-023-00843-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/06/2023] Open
Affiliation(s)
- Guillaume Lebon
- Institut de Génomique Fonctionnelle, Univeristé de Montpellier, CNRS, INSERM, Montpellier, France.
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3
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Perryman R, Renziehausen A, Shaye H, Kostagianni A, Tsiailanis A, Thorne T, Chatziathanasiadou M, Sivolapenko G, El Mubarak MA, Han GW, Zarzycka B, Katritch V, Lebon G, Nigro CL, Lattanzio L, Morse S, Choi J, O’Neill K, Kanaki Z, Klinakis A, Crook T, Cherezov V, Tzakos A, Syed N. EXTH-14. INHIBITION OF THE ANGIOTENSIN II TYPE 2 RECEPTOR AT2R IS A NOVEL THERAPEUTIC STRATEGY FOR GLIOBLASTOMA. Neuro Oncol 2022. [PMCID: PMC9660637 DOI: 10.1093/neuonc/noac209.813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Abstract
Glioblastoma (GBM) is a primary malignant brain tumor with poor clinical outcomes. Standard of care consists of surgical debulking followed by radiation and temozolomide, but the tumor invariably recurs, and median survival is only ~18 months. Repurposing drugs used for the treatment of other diseases is a promising avenue to identify novel treatments for this highly aggressive form of cancer. One such class of compounds is angiotensin II (AngII) receptor blockers, commonly used to control blood pressure. We show that ~80% of primary human GBM express the angiotensin II type 2 receptor (AT2R). In the presence of AngII, inhibition of AT2R using either PD123319 or EMA401 significantly inhibits GBM proliferation. This effect was lost in GBM cells with CRISPR/Cas9 mediated knockdown of AT2R. EMA401 inhibited invasion, angiogenesis, reduced GBM spheroid growth and induced apoptosis through caspase 3/7 activation. Furthermore, EMA401 induced changes in a number of growth regulatory pathways including apoptosis, DNA replication and focal adhesion. The crystal structure of AT2R bound to EMA401 revealed the receptor to be in an active-like conformation with helix-VIII blocking G protein or β-arrestin recruitment. We demonstrate that the architecture and interaction of EMA401 with AT2R differs drastically from complexes of AT2R with other compounds. Conjugation of EMA401 to angiopep-2 enhanced its blood brain barrier passage and reduced tumor volume in an orthotopic xenograft model of GBM. Targeting AT2R is a novel therapeutic strategy to treat GBM that should be explored in patients.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Gye Won Han
- University of Southern California , Los Angeles , USA
| | | | | | | | | | | | - Sophie Morse
- Imperial College London , London , United Kingdom
| | - James Choi
- Imperial College London , London , United Kingdom
| | | | - Zoe Kanaki
- Biomedical Research Foundation of the Academy of Athens , Athens , Greece
| | - Apostolos Klinakis
- Biomedical Research Foundation of the Academy of Athens , Athens , Greece
| | - Tim Crook
- Imperial College London , London , United Kingdom
| | | | | | - Nelofer Syed
- Imperial College London , London , United Kingdom
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4
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Kampen S, Rodríguez D, Jørgensen M, Kruszyk-Kujawa M, Huang X, Collins M, Boyle N, Maurel D, Rudling A, Lebon G, Carlsson J. Structure-Based Discovery of Negative Allosteric Modulators of the Metabotropic Glutamate Receptor 5. ACS Chem Biol 2022; 17:2744-2752. [PMID: 36149353 PMCID: PMC9594040 DOI: 10.1021/acschembio.2c00234] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 01/19/2023]
Abstract
Recently determined structures of class C G protein-coupled receptors (GPCRs) revealed the location of allosteric binding sites and opened new opportunities for the discovery of novel modulators. In this work, molecular docking screens for allosteric modulators targeting the metabotropic glutamate receptor 5 (mGlu5) were performed. The mGlu5 receptor is activated by the main excitatory neurotransmitter of the nervous central system, L-glutamate, and mGlu5 receptor activity can be allosterically modulated by negative or positive allosteric modulators. The mGlu5 receptor is a promising target for the treatment of psychiatric and neurodegenerative diseases, and several allosteric modulators of this GPCR have been evaluated in clinical trials. Chemical libraries containing fragment- (1.6 million molecules) and lead-like (4.6 million molecules) compounds were docked to an allosteric binding site of mGlu5 identified in X-ray crystal structures. Among the top-ranked compounds, 59 fragments and 59 lead-like compounds were selected for experimental evaluation. Of these, four fragment- and seven lead-like compounds were confirmed to bind to the allosteric site with affinities ranging from 0.43 to 8.6 μM, corresponding to a hit rate of 9%. The four compounds with the highest affinities were demonstrated to be negative allosteric modulators of mGlu5 signaling in functional assays. The results demonstrate that virtual screens of fragment- and lead-like chemical libraries have complementary advantages and illustrate how access to high-resolution structures of GPCRs in complex with allosteric modulators can accelerate lead discovery.
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Affiliation(s)
- Stefanie Kampen
- Science
for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, SE-751 24 Uppsala, Sweden
| | - David Rodríguez
- Science
for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, SE-171 21 Solna, Sweden,H.
Lundbeck A/S, Ottiliavej
9, DK-2500 Valby, Denmark
| | | | | | - Xinyan Huang
- Lundbeck
Research USA, 215 College Road, Paramus, New Jersey 07652 - 1431, United States
| | - Michael Collins
- Lundbeck
Research USA, 215 College Road, Paramus, New Jersey 07652 - 1431, United States
| | - Noel Boyle
- Lundbeck
Research USA, 215 College Road, Paramus, New Jersey 07652 - 1431, United States
| | - Damien Maurel
- IGF,
Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Axel Rudling
- Science
for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, SE-171 21 Solna, Sweden
| | - Guillaume Lebon
- IGF,
Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Jens Carlsson
- Science
for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, SE-751 24 Uppsala, Sweden,
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5
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Berto L, Dumazer A, Malhaire F, Cannone G, Kutti Ragunath V, Goudet C, Lebon G. [Recent advances in the structural biology of the class C G protein-coupled receptors: The metabotropic Glutamate receptor 5]. Biol Aujourdhui 2022; 215:85-94. [PMID: 35275053 DOI: 10.1051/jbio/2021013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Class C GPCRs, that include metabotropic glutamate receptors (mGlu), taste receptors, GABAB receptor and Calcium-sensing receptor, are unusual in terms of their molecular architecture and allosteric regulation. They all form obligatory dimers, dimerization being fundamental for their function. More specifically, the mGlu are activated by the main excitatory neurotransmitter, L-glutamate. mGlu activation by glutamate binding in the venus flytrap domain (VFT) triggers conformational changes that are transmitted, through the Cystein-Rich Domain (CRD), to the conserved fold of 7 transmembrane helices (7TM), that couples to intracellular G protein. mGlu activity can also be allosterically modulated by positive (PAM) or negative (NAM) allosteric modulators binding to the 7TM. Recent progress in cryo-electron microscopy (cryoEM) has allowed unprecedented advances in deciphering the structural and molecular basis of their activation mechanism. The agonist induces a large movement between the subunits, bringing the 7TMs together and stabilizing a 7TM conformation structurally similar to the inactive state. The diversity of inactive conformations for the class C was unexpected but allows PAM stabilising a 7TM active conformation independent of the conformational changes induced by agonists, representing an alternative mode of mGlu activation. Here we present and discuss recent structural characterisation of mGlu receptors, highlighting findings that make the class C of GPCR unique. Understanding the structural basis of mGlu dimer signaling represents a landmark achievement and paves the way for structural investigation of GPCR dimer signaling in general. Structural information will open new avenues for structure-based drug design.
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Affiliation(s)
- Ludovic Berto
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Anaëlle Dumazer
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Fanny Malhaire
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | | | | | - Cyril Goudet
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Guillaume Lebon
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
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6
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Affiliation(s)
- Guillaume Lebon
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
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7
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Ricart-Ortega M, Berizzi AE, Catena J, Malhaire F, Muñoz L, Serra C, Lebon G, Goudet C, Llebaria A. Development and validation of a mass spectrometry binding assay for mGlu5 receptor. Anal Bioanal Chem 2020; 412:5525-5535. [PMID: 32564119 DOI: 10.1007/s00216-020-02772-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/03/2020] [Accepted: 06/12/2020] [Indexed: 10/24/2022]
Abstract
Mass spectrometry (MS) binding assays are a label-free alternative to radioligand or fluorescence binding assays, so the readout is based on direct mass spectrometric detection of the test ligand. The study presented here describes the development and validation of a highly sensitive, rapid, and robust MS binding assay for the quantification of the binding of the metabotropic glutamate 5 (mGlu5) negative allosteric modulator (NAM), MPEP (2-methyl-6-phenylethynylpyridine) at the mGlu5 allosteric binding site. The LC-ESI-MS/MS (liquid chromatography-electrospray ionization-tandem mass spectrometric) analytical method was established and validated with a deuterated analogue of MPEP as an internal standard. The developed MS binding assay described here allowed for the determination of MS binding affinity estimates that were in agreement with affinity estimates obtained from a tritiated MPEP radioligand saturation binding assay, indicating the suitability of this methodology for determining affinity estimates for compounds that target mGlu5 allosteric binding sites. Graphical abstract.
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Affiliation(s)
- Maria Ricart-Ortega
- MCS, Laboratory of Medicinal Chemistry & Synthesis, Department of Biological Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18, 08034, Barcelona, Spain.,IGF, CNRS, INSERM, University of Montpellier, 34094, Montpellier, France
| | - Alice E Berizzi
- IGF, CNRS, INSERM, University of Montpellier, 34094, Montpellier, France
| | - Juanlo Catena
- MCS, Laboratory of Medicinal Chemistry & Synthesis, Department of Biological Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18, 08034, Barcelona, Spain
| | - Fanny Malhaire
- IGF, CNRS, INSERM, University of Montpellier, 34094, Montpellier, France
| | - Lourdes Muñoz
- MCS, Laboratory of Medicinal Chemistry & Synthesis, Department of Biological Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18, 08034, Barcelona, Spain.,SIMchem, Service of Synthesis of High Added Value Molecules, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18, 08034, Barcelona, Spain
| | - Carmen Serra
- MCS, Laboratory of Medicinal Chemistry & Synthesis, Department of Biological Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18, 08034, Barcelona, Spain.,SIMchem, Service of Synthesis of High Added Value Molecules, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18, 08034, Barcelona, Spain
| | - Guillaume Lebon
- IGF, CNRS, INSERM, University of Montpellier, 34094, Montpellier, France
| | - Cyril Goudet
- IGF, CNRS, INSERM, University of Montpellier, 34094, Montpellier, France.
| | - Amadeu Llebaria
- MCS, Laboratory of Medicinal Chemistry & Synthesis, Department of Biological Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18, 08034, Barcelona, Spain. .,SIMchem, Service of Synthesis of High Added Value Molecules, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18, 08034, Barcelona, Spain.
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8
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Faucherre A, Moha Ou Maati H, Nasr N, Pinard A, Theron A, Odelin G, Desvignes JP, Salgado D, Collod-Béroud G, Avierinos JF, Lebon G, Zaffran S, Jopling C. Piezo1 is required for outflow tract and aortic valve development. J Mol Cell Cardiol 2020; 143:51-62. [PMID: 32251670 DOI: 10.1016/j.yjmcc.2020.03.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/21/2020] [Accepted: 03/26/2020] [Indexed: 01/26/2023]
Abstract
AIMS During embryogenesis, the onset of circulatory blood flow generates a variety of hemodynamic forces which reciprocally induce changes in cardiovascular development and performance. It has been known for some time that these forces can be detected by as yet unknown mechanosensory systems which in turn promote cardiogenic events such as outflow tract and aortic valve development. PIEZO1 is a mechanosensitive ion channel present in endothelial cells where it serves to detect hemodynamic forces making it an ideal candidate to play a role during cardiac development. We sought to determine whether PIEZO1 is required for outflow tract and aortic valve development. METHODS AND RESULTS By analysing heart development in zebrafish we have determined that piezo1 is expressed in the developing outflow tract where it serves to detect hemodynamic forces. Consequently, disrupting Piezo1 signalling leads to defective outflow tract and aortic valve development and indicates this gene may be involved in the etiology of congenital heart diseases. Based on these findings, we analysed genomic data generated from patients who suffer from left ventricular outflow tract obstructions (LVOTO) and identified 3 probands who each harboured potentially pathogenic variants in PIEZO1. Subsequent in vitro and in vivo assays indicates that these variants behave as dominant negatives leading to an inhibition of normal PIEZO1 mechanosensory activity. Expressing these dominant negative PIEZO1 variants in zebrafish endothelium leads to defective aortic valve development. CONCLUSION These data indicate that the mechanosensitive ion channel piezo1 is required for outflow tract and aortic valve development.
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Affiliation(s)
- Adèle Faucherre
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM LabEx ICST, Montpellier, France
| | - Hamid Moha Ou Maati
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM LabEx ICST, Montpellier, France
| | - Nathalie Nasr
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM LabEx ICST, Montpellier, France
| | - Amélie Pinard
- Aix Marseille Univ, INSERM, MMG UMR1251, 13005 Marseille, France
| | - Alexis Theron
- Aix Marseille Univ, INSERM, MMG UMR1251, 13005 Marseille, France; Service de Chirurgie Cardiaque, AP-HM, Hôpital de la Timone, 13005 Marseille, France
| | - Gaëlle Odelin
- Aix Marseille Univ, INSERM, MMG UMR1251, 13005 Marseille, France
| | | | - David Salgado
- Aix Marseille Univ, INSERM, MMG UMR1251, 13005 Marseille, France
| | | | - Jean-François Avierinos
- Aix Marseille Univ, INSERM, MMG UMR1251, 13005 Marseille, France; Service de Cardiologie, AP-HM, Hôpital de la Timone, 13005 Marseille, France
| | - Guillaume Lebon
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM LabEx ICST, Montpellier, France
| | - Stéphane Zaffran
- Aix Marseille Univ, INSERM, MMG UMR1251, 13005 Marseille, France.
| | - Chris Jopling
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM LabEx ICST, Montpellier, France.
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9
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Nasrallah C, Rottier K, Marcellin R, Compan V, Font J, Llebaria A, Pin JP, Banères JL, Lebon G. Direct coupling of detergent purified human mGlu 5 receptor to the heterotrimeric G proteins Gq and Gs. Sci Rep 2018. [PMID: 29535347 PMCID: PMC5849714 DOI: 10.1038/s41598-018-22729-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [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: 02/04/2023] Open
Abstract
The metabotropic glutamate (mGlu) receptors are class C G protein-coupled receptors (GPCRs) that modulate synaptic activity and plasticity throughout the mammalian brain. Signal transduction is initiated by glutamate binding to the venus flytrap domains (VFT), which initiates a conformational change that is transmitted to the conserved heptahelical domains (7TM) and results ultimately in the activation of intracellular G proteins. While both mGlu1 and mGlu5 activate Gαq G-proteins, they also increase intracellular cAMP concentration through an unknown mechanism. To study directly the G protein coupling properties of the human mGlu5 receptor homodimer, we purified the full-length receptor, which required careful optimisation of the expression, N-glycosylation and purification. We successfully purified functional mGlu5 that activated the heterotrimeric G protein Gq. The high-affinity agonist-PAM VU0424465 also activated the purified receptor in the absence of an orthosteric agonist. In addition, it was found that purified mGlu5 was capable of activating the G protein Gs either upon stimulation with VU0424465 or glutamate, although the later induced a much weaker response. Our findings provide important mechanistic insights into mGlu5 G protein-dependent activity and selectivity.
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Affiliation(s)
- Chady Nasrallah
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France
| | - Karine Rottier
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France
| | - Romain Marcellin
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France
| | - Vincent Compan
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France
| | - Joan Font
- MCS, Laboratory of Medicinal Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
| | - Amadeu Llebaria
- MCS, Laboratory of Medicinal Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France
| | - Jean-Louis Banères
- Institut des Biomolécules Max Mousseron (IBMM), CNRS, Univ. Montpellier, ENSCM, Montpellier, France
| | - Guillaume Lebon
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France.
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10
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Abstract
Adenosine receptors (ARs) comprise the P1 class of purinergic receptors and belong to the largest family of integral membrane proteins in the human genome, the G protein-coupled receptors (GPCRs). ARs are classified into four subtypes, A1, A2A, A2B, and A3, which are all activated by extracellular adenosine, and play central roles in a broad range of physiological processes, including sleep regulation, angiogenesis and modulation of the immune system. ARs are potential therapeutic targets in a variety of pathophysiological conditions, including sleep disorders, cancer, and dementia, which has made them important targets for structural biology. Over a decade of research and innovation has culminated with the publication of more than 30 crystal structures of the human adenosine A2A receptor (A2AR), making it one of the best structurally characterized GPCRs at the atomic level. In this review we analyze the structural data reported for A2AR that described for the first time the binding of mode of antagonists, including newly developed drug candidates, synthetic and endogenous agonists, sodium ions and an engineered G protein. These structures have revealed the key conformational changes induced upon agonist and G protein binding that are central to signal transduction by A2AR, and have highlighted both similarities and differences in the activation mechanism of this receptor compared to other class A GPCRs. Finally, comparison of A2AR with the recently solved structures of A1R has provided the first structural insight into the molecular determinants of ligand binding specificity in different AR subtypes.
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Affiliation(s)
- Byron Carpenter
- Warwick Integrative Synthetic Biology Centre, School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Guillaume Lebon
- Institut de Génomique Fonctionnelle, Neuroscience Department, UMR CNRS 5203, INSERM U1191, Université de Montpellier, Montpellier, France
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11
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Venkatakrishnan AJ, Deupi X, Lebon G, Heydenreich FM, Flock T, Miljus T, Balaji S, Bouvier M, Veprintsev DB, Tate CG, Schertler GFX, Babu MM. Diverse activation pathways in class A GPCRs converge near the G-protein-coupling region. Nature 2016; 536:484-7. [PMID: 27525504 DOI: 10.1038/nature19107] [Citation(s) in RCA: 212] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 07/13/2016] [Indexed: 02/06/2023]
Abstract
Class A G-protein-coupled receptors (GPCRs) are a large family of membrane proteins that mediate a wide variety of physiological functions, including vision, neurotransmission and immune responses. They are the targets of nearly one-third of all prescribed medicinal drugs such as beta blockers and antipsychotics. GPCR activation is facilitated by extracellular ligands and leads to the recruitment of intracellular G proteins. Structural rearrangements of residue contacts in the transmembrane domain serve as 'activation pathways' that connect the ligand-binding pocket to the G-protein-coupling region within the receptor. In order to investigate the similarities in activation pathways across class A GPCRs, we analysed 27 GPCRs from diverse subgroups for which structures of active, inactive or both states were available. Here we show that, despite the diversity in activation pathways between receptors, the pathways converge near the G-protein-coupling region. This convergence is mediated by a highly conserved structural rearrangement of residue contacts between transmembrane helices 3, 6 and 7 that releases G-protein-contacting residues. The convergence of activation pathways may explain how the activation steps initiated by diverse ligands enable GPCRs to bind a common repertoire of G proteins.
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12
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Magnani F, Serrano-Vega MJ, Shibata Y, Abdul-Hussein S, Lebon G, Miller-Gallacher J, Singhal A, Strege A, Thomas JA, Tate CG. A mutagenesis and screening strategy to generate optimally thermostabilized membrane proteins for structural studies. Nat Protoc 2016; 11:1554-71. [PMID: 27466713 PMCID: PMC5268090 DOI: 10.1038/nprot.2016.088] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The thermostability of an integral membrane protein (MP) in detergent solution is a key parameter that dictates the likelihood of obtaining well-diffracting crystals that are suitable for structure determination. However, many mammalian MPs are too unstable for crystallization. We developed a thermostabilization strategy based on systematic mutagenesis coupled to a radioligand-binding thermostability assay that can be applied to receptors, ion channels and transporters. It takes ∼6-12 months to thermostabilize a G-protein-coupled receptor (GPCR) containing 300 amino acid (aa) residues. The resulting thermostabilized MPs are more easily crystallized and result in high-quality structures. This methodology has facilitated structure-based drug design applied to GPCRs because it is possible to determine multiple structures of the thermostabilized receptors bound to low-affinity ligands. Protocols and advice are given on how to develop thermostability assays for MPs and how to combine mutations to make an optimally stable mutant suitable for structural studies. The steps in the procedure include the generation of ∼300 site-directed mutants by Ala/Leu scanning mutagenesis, the expression of each mutant in mammalian cells by transient transfection and the identification of thermostable mutants using a thermostability assay that is based on binding of an (125)I-labeled radioligand to the unpurified, detergent-solubilized MP. Individual thermostabilizing point mutations are then combined to make an optimally stable MP that is suitable for structural biology and other biophysical studies.
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Affiliation(s)
| | | | | | | | | | | | - Ankita Singhal
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Annette Strege
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Jennifer A. Thomas
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Christopher G. Tate
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
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13
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Lebon G, Machrafi H, Grmela M. An extended irreversible thermodynamic modelling of size-dependent thermal conductivity of spherical nanoparticles dispersed in homogeneous media. Proc Math Phys Eng Sci 2015. [DOI: 10.1098/rspa.2015.0144] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The effective thermal conductivity of nanocomposites constituted by nanoparticles and homogeneous host media is discussed from the point of view of extended irreversible thermodynamics. This formalism is particularly well adapted to the description of small length scales. As illustrations, dispersion of Si nanoparticles in Ge (respectively, SiO
2
in epoxy resin) homogeneous matrices is investigated, the nanoparticles are assumed to be spherical with a wide dispersion. Four specific problems are studied: the dependence of the effective thermal conductivity on the volume fraction of particles, the type of phonon scattering at the interface particle–matrix, the radius of the nanoparticles and the temperature.
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Affiliation(s)
- G. Lebon
- Thermodynamics of Irreversible Processes, Liège University, Allée du 6 août, Liège 4000, Belgium
| | - H. Machrafi
- Thermodynamics of Irreversible Processes, Liège University, Allée du 6 août, Liège 4000, Belgium
| | - M. Grmela
- Department of Chemical Engineering, Ecole Polytechnique de Montréal, Montréal, Canada H3C 3A7
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14
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Lebon G, Edwards PC, Leslie AGW, Tate CG. Molecular Determinants of CGS21680 Binding to the Human Adenosine A2A Receptor. Mol Pharmacol 2015; 87:907-15. [PMID: 25762024 DOI: 10.1124/mol.114.097360] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 03/11/2015] [Indexed: 11/22/2022] Open
Abstract
The adenosine A2A receptor (A(2A)R) plays a key role in transmembrane signaling mediated by the endogenous agonist adenosine. Here, we describe the crystal structure of human A2AR thermostabilized in an active-like conformation bound to the selective agonist 2-[p-(2-carboxyethyl)phenylethyl-amino]-5'-N-ethylcarboxamido adenosine (CGS21680) at a resolution of 2.6 Å. Comparison of A(2A)R structures bound to either CGS21680, 5'-N-ethylcarboxamido adenosine (NECA), UK432097 [6-(2,2-diphenylethylamino)-9-[(2R,3R,4S,5S)-5-(ethylcarbamoyl)-3,4-dihydroxy-tetrahydrofuran-2-yl]-N-[2-[[1-(2-pyridyl)-4-piperidyl]carbamoylamino]ethyl]purine-2-carboxamide], or adenosine shows that the adenosine moiety of the ligands binds to the receptor in an identical fashion. However, an extension in CGS21680 compared with adenosine, the (2-carboxyethyl)phenylethylamino group, binds in an extended vestibule formed from transmembrane regions 2 and 7 (TM2 and TM7) and extracellular loops 2 and 3 (EL2 and EL3). The (2-carboxyethyl)phenylethylamino group makes van der Waals contacts with side chains of amino acid residues Glu169(EL2), His264(EL3), Leu267(7.32), and Ile274(7.39), and the amine group forms a hydrogen bond with the side chain of Ser67(2.65). Of these residues, only Ile274(7.39) is absolutely conserved across the human adenosine receptor subfamily. The major difference between the structures of A(2A)R bound to either adenosine or CGS21680 is that the binding pocket narrows at the extracellular surface when CGS21680 is bound, due to an inward tilt of TM2 in that region. This conformation is stabilized by hydrogen bonds formed by the side chain of Ser67(2.65) to CGS21680, either directly or via an ordered water molecule. Mutation of amino acid residues Ser67(2.65), Glu169(EL2), and His264(EL3), and analysis of receptor activation either in the presence or absence of ligands implicates this region in modulating the level of basal activity of A(2A)R.
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Affiliation(s)
- Guillaume Lebon
- Institut de Génomique Fonctionelle, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5203, Institut National de la Sante et de la Recherche Medicale U1191, Université de Montpellier, Montpellier, France (G.L.); and Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom (P.C.E., A.G.W.L., C.G.T.)
| | - Patricia C Edwards
- Institut de Génomique Fonctionelle, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5203, Institut National de la Sante et de la Recherche Medicale U1191, Université de Montpellier, Montpellier, France (G.L.); and Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom (P.C.E., A.G.W.L., C.G.T.)
| | - Andrew G W Leslie
- Institut de Génomique Fonctionelle, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5203, Institut National de la Sante et de la Recherche Medicale U1191, Université de Montpellier, Montpellier, France (G.L.); and Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom (P.C.E., A.G.W.L., C.G.T.)
| | - Christopher G Tate
- Institut de Génomique Fonctionelle, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5203, Institut National de la Sante et de la Recherche Medicale U1191, Université de Montpellier, Montpellier, France (G.L.); and Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom (P.C.E., A.G.W.L., C.G.T.)
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15
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Abstract
Crystallization of G protein-coupled receptors (GPCRs) is successful due to the development of generic protein engineering strategies, which has resulted in the structure determination of more than 25 GPCRs, including representatives from class A, B, C, and F. Most of the X-ray structures available correspond to an inactive conformation of the receptor bound to an antagonist. Only a few high-resolution structures of agonist-bound conformations of GPCRs have been determined over the last 6 years. Here, we describe the purification and crystallization protocols of a thermostabilized agonist-bound conformation of the human adenosine A2A receptor.
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Affiliation(s)
- Christopher G Tate
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK,
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16
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Bennett KA, Tehan B, Lebon G, Tate CG, Weir M, Marshall FH, Langmead CJ. Pharmacology and structure of isolated conformations of the adenosine A₂A receptor define ligand efficacy. Mol Pharmacol 2013; 83:949-58. [PMID: 23429888 DOI: 10.1124/mol.112.084509] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Using isolated receptor conformations crystal structures of the adenosine A₂A receptor have been solved in active and inactive states. Studying the change in affinity of ligands at these conformations allowed qualitative prediction of compound efficacy in vitro in a system-independent manner. Agonist 5'-N-ethylcarboxamidoadenosine displayed a clear preference to bind to the active state receptor; inverse agonists (xanthine amine congener, ZM241385, SCH58261, and preladenant) bound preferentially to the inactive state, whereas neutral antagonists (theophylline, caffeine, and istradefylline) demonstrated equal affinity for active and inactive states. Ligand docking into the known crystal structures of the A₂A receptor rationalized the pharmacology observed; inverse agonists, unlike neutral antagonists, cannot be accommodated within the agonist-binding site of the receptor. The availability of isolated receptor conformations opens the door to the concept of "reverse pharmacology" whereby the functional pharmacology of ligands can be characterized in a system-independent manner by their affinity for a pair (or set) of G protein-coupled receptor conformations.
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Affiliation(s)
- Kirstie A Bennett
- Heptares Therapeutics Ltd, Welwyn Garden City, Hertfordshire, United Kingdom
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17
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Abstract
G protein-coupled receptors (GPCR) are the largest family of integral membrane proteins found in the plasma membrane of mammalian cells. GPCR respond to a large variety of ligands such as amines, lipids, hormones and amino-acids, which are involved in inter-cellular signalling events in a multitude of physiological and pathological processes. GPCRs are therefore key regulators of signal transduction by which cells respond to variations in their environment. During the last five years, striking progress has been made to solve high-resolution structure of GPCR. The most recent successes are the structures of the β(1) and β(2) adrenoreceptors and the adenosine A(2A) receptor bound to a variety of agonists. Most importantly, the structure of the β(2) adrenoreceptor in complex with a trimeric G protein, Gs, was recently reported. This review will present an overview of the X-ray structure determination of the GPCR and of their activation mechanism.
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Affiliation(s)
- Guillaume Lebon
- Département de Pharmacologie Moléculaire, Universités de Montpellier I et II, Montpellier, France.
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18
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Owen RL, Axford D, Nettleship JE, Owens RJ, Robinson JI, Morgan AW, Doré AS, Lebon G, Tate CG, Fry EE, Ren J, Stuart DI, Evans G. Outrunning free radicals in room-temperature macromolecular crystallography. Acta Crystallogr D Biol Crystallogr 2012; 68:810-8. [PMID: 22751666 PMCID: PMC4791751 DOI: 10.1107/s0907444912012553] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 03/22/2012] [Indexed: 11/13/2022]
Abstract
A significant increase in the lifetime of room-temperature macromolecular crystals is reported through the use of a high-brilliance X-ray beam, reduced exposure times and a fast-readout detector. This is attributed to the ability to collect diffraction data before hydroxyl radicals can propagate through the crystal, fatally disrupting the lattice. Hydroxyl radicals are shown to be trapped in amorphous solutions at 100 K. The trend in crystal lifetime was observed in crystals of a soluble protein (immunoglobulin γ Fc receptor IIIa), a virus (bovine enterovirus serotype 2) and a membrane protein (human A(2A) adenosine G-protein coupled receptor). The observation of a similar effect in all three systems provides clear evidence for a common optimal strategy for room-temperature data collection and will inform the design of future synchrotron beamlines and detectors for macromolecular crystallography.
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Affiliation(s)
- Robin L Owen
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England.
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19
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Lebon G, Warne T, Tate CG. Agonist-bound structures of G protein-coupled receptors. Curr Opin Struct Biol 2012; 22:482-90. [PMID: 22480933 DOI: 10.1016/j.sbi.2012.03.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/12/2012] [Accepted: 03/14/2012] [Indexed: 01/14/2023]
Abstract
G protein-coupled receptors (GPCRs) play a major role in intercellular communication by binding small diffusible ligands (agonists) at the extracellular surface. Agonist-binding induces a conformational change in the receptor, which results in the binding and activation of heterotrimeric G proteins within the cell. Ten agonist-bound structures of non-rhodopsin GPCRs published last year defined for the first time the molecular details of receptor activated states and how inverse agonists, partial agonists and full agonists bind to produce different effects on the receptor. In addition, the structure of the β(2)-adrenoceptor coupled to a heterotrimeric G protein showed how the opening of a cleft in the cytoplasmic face of the receptor as a consequence of agonist binding results in G protein coupling and activation of the G protein.
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Affiliation(s)
- Guillaume Lebon
- Institut de Génomique Fonctionnelle, UMR 5203 CNRS - U 661 INSERM - Univ. Montpellier I & II, 141, rue de la cardonille, 34094 Montpellier Cedex 05, France
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20
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21
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Abstract
A thermodynamic description of transient heat conduction at small length and timescales is proposed. It is based on extended irreversible thermodynamics and the main feature of this formalism is to elevate the heat flux vector to the status of independent variable at the same level as the classical variable, the temperature. The present model assumes the coexistence of two kinds of heat carriers: diffusive and ballistic phonons. The behaviour of the diffusive phonons is governed by a Cattaneo-type equation to take into account the high-frequency phenomena generally present at nanoscales. To include non-local effects that are dominant in nanostructures, it is assumed that the ballistic carriers are obeying a Guyer–Krumhansl relation. The model is applied to the problem of transient heat conduction through a thin nanofilm. The numerical results are compared with those provided by Fourier, Cattaneo and other recent models.
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Affiliation(s)
- G. Lebon
- Department of Astrophysics, Geophysics and Oceanography, Liège University, Allée du 6 Août, 17, 4000 Liège, Belgium
| | - H. Machrafi
- Department of Astrophysics, Geophysics and Oceanography, Liège University, Allée du 6 Août, 17, 4000 Liège, Belgium
| | - M. Grmela
- Ecole Polytechnique, Center for Applied Research on Polymers and Composites, Montreal, H3C3A7, Canada
| | - Ch. Dubois
- Ecole Polytechnique, Center for Applied Research on Polymers and Composites, Montreal, H3C3A7, Canada
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22
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Lebon G, Warne T, Edwards PC, Bennett K, Langmead CJ, Leslie AGW, Tate CG. Agonist-bound adenosine A2A receptor structures reveal common features of GPCR activation. Nature 2011; 474:521-5. [PMID: 21593763 PMCID: PMC3146096 DOI: 10.1038/nature10136] [Citation(s) in RCA: 671] [Impact Index Per Article: 51.6] [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] [Received: 02/22/2011] [Accepted: 04/21/2011] [Indexed: 12/18/2022]
Abstract
Adenosine receptors and β-adrenoceptors are G-protein-coupled receptors (GPCRs) that activate intracellular G proteins on binding the agonists adenosine or noradrenaline, respectively. GPCRs have similar structures consisting of seven transmembrane helices that contain well-conserved sequence motifs, indicating that they are probably activated by a common mechanism. Recent structures of β-adrenoceptors highlight residues in transmembrane region 5 that initially bind specifically to agonists rather than to antagonists, indicating that these residues have an important role in agonist-induced activation of receptors. Here we present two crystal structures of the thermostabilized human adenosine A(2A) receptor (A(2A)R-GL31) bound to its endogenous agonist adenosine and the synthetic agonist NECA. The structures represent an intermediate conformation between the inactive and active states, because they share all the features of GPCRs that are thought to be in a fully activated state, except that the cytoplasmic end of transmembrane helix 6 partially occludes the G-protein-binding site. The adenine substituent of the agonists binds in a similar fashion to the chemically related region of the inverse agonist ZM241385 (ref. 8). Both agonists contain a ribose group, not found in ZM241385, which extends deep into the ligand-binding pocket where it makes polar interactions with conserved residues in H7 (Ser 277(7.42) and His 278(7.43); superscripts refer to Ballesteros-Weinstein numbering) and non-polar interactions with residues in H3. In contrast, the inverse agonist ZM241385 does not interact with any of these residues and comparison with the agonist-bound structures indicates that ZM241385 sterically prevents the conformational change in H5 and therefore it acts as an inverse agonist. Comparison of the agonist-bound structures of A(2A)R with the agonist-bound structures of β-adrenoceptors indicates that the contraction of the ligand-binding pocket caused by the inward motion of helices 3, 5 and 7 may be a common feature in the activation of all GPCRs.
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Affiliation(s)
- Guillaume Lebon
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
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23
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Gorrec F, Palmer CM, Lebon G, Warne T. Pi sampling: a methodical and flexible approach to initial macromolecular crystallization screening. Acta Crystallogr D Biol Crystallogr 2011; 67:463-70. [PMID: 21543849 PMCID: PMC3087625 DOI: 10.1107/s0907444911008754] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 03/07/2011] [Indexed: 11/29/2022]
Abstract
The Pi sampling method is derived from the incomplete factorial approach to macromolecular crystallization screen design. The resulting `Pi screens' have a modular distribution of a given set of up to 36 stock solutions. Maximally diverse conditions can be produced by taking into account the properties of the chemicals used in the formulation and the concentrations of the corresponding solutions. The Pi sampling method has been implemented in a web-based application that generates screen formulations and recipes. It is particularly adapted to screens consisting of 96 different conditions. The flexibility and efficiency of Pi sampling is demonstrated by the crystallization of soluble proteins and of an integral membrane-protein sample.
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Affiliation(s)
- Fabrice Gorrec
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB20QH, England.
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Lebon G, Bennett K, Jazayeri A, Tate CG. Thermostabilisation of an agonist-bound conformation of the human adenosine A(2A) receptor. J Mol Biol 2011; 409:298-310. [PMID: 21501622 PMCID: PMC3145977 DOI: 10.1016/j.jmb.2011.03.075] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 03/31/2011] [Accepted: 03/31/2011] [Indexed: 11/02/2022]
Abstract
The adenosine A(2A) receptor (A(2A)R) is a G-protein-coupled receptor that plays a key role in transmembrane signalling mediated by the agonist adenosine. The structure of A(2A)R was determined recently in an antagonist-bound conformation, which was facilitated by the T4 lysozyme fusion in cytoplasmic loop 3 and the considerable stabilisation conferred on the receptor by the bound inverse agonist ZM241385. Unfortunately, the natural agonist adenosine does not sufficiently stabilise the receptor for the formation of diffraction-quality crystals. As a first step towards determining the structure of A(2A)R bound to an agonist, the receptor was thermostabilised by systematic mutagenesis in the presence of the bound agonist [(3)H]5'-N-ethylcarboxamidoadenosine (NECA). Four thermostabilising mutations were identified that when combined to give mutant A(2A)R-GL26, conferred a greater than 200-fold decrease in its rate of unfolding compared to the wild-type receptor. Pharmacological analysis suggested that A(2A)R-GL26 is stabilised in an agonist-bound conformation because antagonists bind with up to 320-fold decreased affinity. None of the thermostabilising mutations are in the ZM241385 binding pocket, suggesting that the mutations affect ligand binding by altering the conformation of the receptor rather than through direct interactions with ligands. A(2A)R-GL26 shows considerable stability in short-chain detergents, which has allowed its purification and crystallisation.
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Jou D, Lebon G, Criado-Sancho M. Variational principles for thermal transport in nanosystems with heat slip flow. Phys Rev E Stat Nonlin Soft Matter Phys 2010; 82:031128. [PMID: 21230046 DOI: 10.1103/physreve.82.031128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Indexed: 05/30/2023]
Abstract
Some years ago, Prigogine minimum entropy production principle was generalized by Lebon and Dauby to account for the nonlocal heat transport equation derived by Guyer and Krumhansl. Here, this criterion is extended to incorporate the effects of heat slip flow along the walls. This formulation is shown to be useful for the description of steady heat flow in nanosystems, where the heat slip flow plays a decisive role.
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Affiliation(s)
- D Jou
- Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Catalonia, Spain.
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26
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Lebon G, Langmead CJ, Tehan BG, Hulme EC. Mutagenic mapping suggests a novel binding mode for selective agonists of M1 muscarinic acetylcholine receptors. Mol Pharmacol 2008; 75:331-41. [PMID: 19001633 DOI: 10.1124/mol.108.050963] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Point mutations and molecular modeling have been used to study the activation of the M(1) muscarinic acetylcholine receptor (mAChR) by the functionally selective agonists 4-n-butyl-1-[4-(2-methylphenyl)-4-oxo-1-butyl]-piperidine (AC-42), and 1-[3-(4-butyl-1-piperidinyl)propyl]-3,4-dihydro-2(1H)-quinolinone (77-LH-28-1), comparing them with N-desmethylclozapine (NDMC) and acetylcholine (ACh). Unlike NDMC and ACh, the activities of AC-42 and 77-LH-28-1 were undiminished by mutations of Tyr404 and Cys407 (transmembrane helix 7), although they were reduced by mutations of Tyr408. Signaling by AC-42, 77-LH-28-1, and NDMC was reduced by L102A and abolished by D105E, suggesting that all three may interact with transmembrane helix 3 at or near the binding site Asp105 to activate the M(1) mAChR. In striking contrast to NDMC and ACh, the affinities of AC-42 and 77-LH-28-1 were increased 100-fold by W101A, and their signaling activities were abolished by Y82A. Tyr82 and Leu102 contact the indole ring of Trp101 in a structural model of the M(1) mAChR. We suggest the hypothesis that the side chain of Trp101 undergoes conformational isomerization, opening a novel binding site for the aromatic side chain of the AC-42 analogs. This may allow the positively charged piperidine nitrogen of the ligands to access the neighboring Asp105 carboxylate to activate signaling following a vector within the binding site that is distinct from that of acetylcholine. NDMC does not seem to use this mechanism. Subtype-specific differences in the free energy of rotation of the side chain and indole ring of Trp101 might underlie the M(1) selectivity of the AC-42 analogs. Tryptophan conformational isomerization may open up new avenues in selective muscarinic receptor drug design.
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Affiliation(s)
- Guillaume Lebon
- Division of Physical Biochemistry, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
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Lebon G, Wojnarowiez G, Holzapfel B, Fontaine F, Vaillant-Gaveau N, Clément C. Sugars and flowering in the grapevine (Vitis vinifera L.). J Exp Bot 2008; 59:2565-78. [PMID: 18508810 DOI: 10.1093/jxb/ern135] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Sugars play an important role in grapevine flowering. This complex process from inflorescence initiation to fruit maturity takes two growing seasons. Currently, most of the available data concern the involvement of sugars as energy sources during the formation of reproductive structures from initiation of inflorescences during the summer of the first year, until flower opening during the following spring. Sugars devoted to the development of reproductive structures are supplied either by wood reserves or by photosynthesis in leaves or inflorescences, depending on the stage of development. Female meiosis appears to be a key point in the success of flower formation because (i) flowers are vulnerable at this stage and (ii) it corresponds in the whole plant to the transition between reserve mobilization from perennial organs (roots, trunk, and canes) towards efficient leaf photosynthesis. The perturbation of reserve replenishment during the previous year provokes perturbation in the development of inflorescences, whereas altering the photosynthetic sources affects the formation of flowers during the same year. In particular, a lack of sugar availability in flowers at female meiosis caused by various environmental or physiological fluctuations may lead to drastic flower abortion. Apart from energy, sugars also play roles as regulators of gene expression and as signal molecules that may be involved in stress responses. In the future, these two topics should be further investigated in the grapevine considering the sensitivity of flowers to environmental stresses at meiosis.
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Affiliation(s)
- G Lebon
- URVVC-EA 2069, Stress, Défenses et Reproduction des Plantes, Université de Reims Champagne-Ardenne, BP 1039, F-51687 Reims cedex 2, France
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28
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Jou D, Casas-Vázquez J, Lebon G. Extended irreversible thermodynamics of heat transport. A brief introduction. Proc Estonian Acad Sci 2008. [DOI: 10.3176/proc.2008.3.01] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
Large scale comparative evaluation of protein expression requires miniaturized techniques to provide sensitive and accurate measurements of the abundance of molecules present as individual and/or assembled protein complexes in cells. The principle of competition between target molecules for binding to arrayed antibodies has recently been proposed to assess differential expression of numerous proteins with one-color or two-color fluorescence detection methods. To establish the limiting factors and to validate the use of alternative detection for protein profiling, we performed competitive binding assays under different conditions. A model experimental protocol was developed whereby the competitive displacement of multi-subunit bacterial RNA polymerase and/or its subunits was evaluated through binding to subunit-specific immobilized monoclonal antibodies. We show that the difference in physico-chemical properties of unlabeled and labeled molecules significantly affects the performance of one-color detection, whereas epitope inaccessibility in the protein complex can prohibit the assessment of competition by both detection methods. Our data also demonstrate that antibody cross-reactivity, target protein truncation and abundance, as well as the cellular compartment of origin are major factors that affect protein profiling on antibody arrays. The experimental conditions established for prokaryotic proteins were adopted to compare protein profiles in the breast tumor-derived cell lines MDA MB-231 and SKBR3. Competitive displacement was detected and confirmed for a number of proteins using both detection methods; however, we show that overall the two-color method is better suited for accurate expression profile evaluation of a large, complex set of proteins. Antibody array data confirm the functional linkage between the ErbB2 receptor and AP-2 transcription factors in these cell lines and highlight unexpected differences in G1 cyclin expression.
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Affiliation(s)
- Garabet Yeretssian
- Biotechnologie, Biocatalyse, Biorégulation, Unité Mixte de Recherche 6204, Centre National de la Recherche Scientifique, Université de Nantes, 2 rue de la Houssinière, 44322 Nantes, France
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Madruga S, Pérez-García C, Lebon G. Convective instabilities in two superposed horizontal liquid layers heated laterally. Phys Rev E Stat Nonlin Soft Matter Phys 2003; 68:041607. [PMID: 14682953 DOI: 10.1103/physreve.68.041607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2003] [Indexed: 05/24/2023]
Abstract
This work is devoted to the theoretical study of the stability of two superposed horizontal liquid layers bounded by two solid planes and subjected to a horizontal temperature gradient. The liquids are supposed to be immiscible with a nondeformable interface. The forces acting on the system are buoyancy and interfacial tension. Four different flow patterns and temperature profiles are found for the basic state. A linear perturbative analysis with respect to two- and three-dimensional perturbations reveals the existence of three kinds of patterns. Depending on the relative height of both liquids several situations are predicted: either wave propagation from cold to the hot regions, or waves propagating in the opposite direction or still stationary longitudinal rolls. The behavior of three different pairs of liquids which have been used in experiments on bilayers under vertical gradient by other authors have been examined. The instability mechanisms are discussed and a qualitative interpretation of the different behaviors exhibited by the system is provided. In some configurations it is possible to find a codimension-two point created by the interaction of two Hopf modes with different frequencies and wave numbers. These results suggest to consider two liquid layers as an interesting prototype for the study of propagation and interaction of waves in the context of the Bénard-Marangoni problem.
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Affiliation(s)
- S Madruga
- Departement AGO, Liège University, B5, Sart-Tilman, B-4000 Liège, Belgium.
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Margerit J, Colinet P, Lebon G, Iorio CS, Legros JC. Interfacial nonequilibrium and Bénard-Marangoni instability of a liquid-vapor system. Phys Rev E Stat Nonlin Soft Matter Phys 2003; 68:041601. [PMID: 14682947 DOI: 10.1103/physreve.68.041601] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2002] [Revised: 10/16/2002] [Indexed: 05/24/2023]
Abstract
We study Bénard-Marangoni instability in a system formed by a horizontal liquid layer and its overlying vapor. The liquid is lying on a hot rigid plate and the vapor is bounded by a cold parallel plate. A pump maintains a reduced pressure in the vapor layer and evacuates the vapor. This investigation is undertaken within the classical quasisteady approximation for both the vapor and the liquid phases. The two layers are separated by a deformable interface. Temporarily frozen temperature and velocity distributions are employed at each instant for the stability analysis, limited to infinitesimal disturbances (linear regime). We use irreversible thermodynamics to model the phase change under interfacial nonequilibrium. Within this description, the interface appears as a barrier for transport of both heat and mass. Hence, in contrast with previous studies, we consider the possibility of a temperature jump across the interface, as recently measured experimentally. The stability analysis shows that the interfacial resistances to heat and mass transfer have a destabilizing influence compared to an interface that is in thermodynamic equilibrium. The role of the fluctuations in the vapor phase on the onset of instability is discussed. The conditions to reduce the system to a one phase model are also established. Finally, the influence of the evaporation parameters and of the presence of an inert gas on the marginal stability curves is discussed.
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Affiliation(s)
- J Margerit
- University of Liège, Institute of Astrophysics and Geophysics, B5, Sart-Tilman, B-4000 Liège, Belgium
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Desaive T, Lebon G, Hennenberg M. Coupled capillary and gravity-driven instability in a liquid film overlying a porous layer. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 64:066304. [PMID: 11736273 DOI: 10.1103/physreve.64.066304] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2001] [Indexed: 05/23/2023]
Abstract
In this work, we study the problem of onset of thermal convection in a fluid layer overlying a porous layer, the whole system being heated from below. We use Brinkman's model to describe the porous medium and determine the corresponding linear stability equations. The eigenvalue problem is solved by means of a modified Galerkin method. The behavior of the critical wave number and temperature gradient is discussed in terms of the various parameters of the system. We also emphasize the influence of the boundary conditions at the upper surface of the fluid layer; in particular, we examine the role of a free surface whose surface tension is temperature dependent (Marangoni effect). Comparison with earlier works is also made.
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Affiliation(s)
- T Desaive
- University of Liège, Institute of Physics, B5, B-4000 Liège, Belgium.
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Abstract
The effect of different mass transfer mechanisms on the Marangoni instability in a two-layer system of finite width is studied. A dilute soluble surfactant is transferred across the interface between two immiscible fluid phases. A linear stability analysis is developed, and the corresponding eigenvalue problem is solved analytically for the onset of monotonic instability. Mass transfer is assumed to be controlled by bulk diffusion or/and by the adsorption-desorption mechanism. The influences of the diffusivity ratio and the layer width ratio on the instability of the system are examined. Copyright 1998 Academic Press.
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Affiliation(s)
- S Slavtchev
- Institute of Mechanics, Bulgarian Academy of Sciences, Acad. G. Bontchev St., Block 4, Sofia, 1113, Bulgaria
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Thévenot T, Permal S, Dhôte R, Farrenq V, Tulliez M, Lebon G, Christoforov B. Mononucléose infectieuse : deux observations inhabituelles d'hépatite à Epstein-Barr virus. Rev Med Interne 1998. [DOI: 10.1016/s0248-8663(98)90179-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Vasconcellos AR, Luzzi R, Lebon G. Heat transport in a boson system: An information-theoretical approach. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1996; 54:4738-4747. [PMID: 9965652 DOI: 10.1103/physreve.54.4738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Colinet P, Géoris P, Legros JC, Lebon G. Spatially quasiperiodic convection and temporal chaos in two-layer thermocapillary instabilities. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1996; 54:514-524. [PMID: 9965095 DOI: 10.1103/physreve.54.514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Parmentier PM, Regnier VC, Lebon G, Legros JC. Nonlinear analysis of coupled gravitational and capillary thermoconvention in thin fluid layers. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1996; 54:411-423. [PMID: 9965084 DOI: 10.1103/physreve.54.411] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Dedeurwaerdere T, Casas-Vázquez J, Jou D, Lebon G. Foundations and applications of a mesoscopic thermodynamic theory of fast phenomena. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1996; 53:498-506. [PMID: 9964280 DOI: 10.1103/physreve.53.498] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Colinet P, Legros JC, Kamotani Y, Dauby PC, Lebon G. Finite-amplitude regimes of the short-wave Marangoni-Benard convective instability. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1995; 52:2603-2616. [PMID: 9963706 DOI: 10.1103/physreve.52.2603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Urabe T, Baker ET, Ishibashi J, Feely RA, Marumo K, Massoth GJ, Maruyama A, Shitashima K, Okamura K, Lupton JE, Sonoda A, Yamazaki T, Aoki M, Gendron J, Greene R, Kaiho Y, Kisimoto K, Lebon G, Matsumoto T, Nakamura K, Nishizawa A, Okano O, Paradis G, Roe K, Shibata T, Tennant D, Vance T, Walker SL, Yabuki T, Ytow N. The Effect of Magmatic Activity on Hydrothermal Venting Along the Superfast-Spreading East Pacific Rise. Science 1995; 269:1092-5. [PMID: 17755532 DOI: 10.1126/science.269.5227.1092] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A survey of hydrothermal activity along the superfast-spreading (approximately 150 millimeters per year) East Pacific Rise shows that hydrothermal plumes overlay approximately 60 percent of the ridge crest between 13 degrees 50' and 18 degrees 40'S, a plume abundance nearly twice that known from any other rige portion of comparable length. Plumes were most abundant where the axial cross section is inflated and an axial magma chamber is present. Plumes with high ratios of volatile ((3)He, CH(4), and H(2)S) to nonvolatile (Mn and Fe) species marked where hydrothermal circulation has been perturbed by recent magmatic activity. The high proportion of volatile-rich plumes observed implies that such episodes are more frequent here than on slower spreading ridges.
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Lebon G, Casas‐Vázquez J, Jou D, Criado‐Sancho M. Polymer solutions and chemical reactions under flow: A thermodynamic description. J Chem Phys 1993. [DOI: 10.1063/1.464707] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Lebon G, Dauby PC. Heat transport in dielectric crystals at low temperature: A variational formulation based on extended irreversible thermodynamics. Phys Rev A 1990; 42:4710-4715. [PMID: 9904578 DOI: 10.1103/physreva.42.4710] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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