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Grosse C, Sigoillot M, Megalizzi V, Tanina A, Willand N, Baulard AR, Wintjens R. Crystal structure of the Mycobacterium tuberculosis VirS regulator reveals its interaction with the lead compound SMARt751. J Struct Biol 2024; 216:108090. [PMID: 38548139 DOI: 10.1016/j.jsb.2024.108090] [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: 01/23/2024] [Revised: 03/25/2024] [Accepted: 03/25/2024] [Indexed: 04/02/2024]
Abstract
Ethionamide (ETO) is a prodrug that is primarily used as a second-line agent in the treatment of tuberculosis. Among the bacterial ETO activators, the monooxygenase MymA has been recently identified, and its expression is regulated by the mycobacterial regulator VirS. The discovery of VirS ligands that can enhance mymA expression and thereby increase the antimycobacterial efficacy of ETO, has led to the development of a novel therapeutic strategy against tuberculosis. This strategy involves the selection of preclinical candidates, including SMARt751. We report the first crystal structure of the AraC-like regulator VirS, in complex with SMARt751, refined at 1.69 Å resolution. Crystals were obtained via an in situ proteolysis method in the requisite presence of SMARt751. The elucidated structure corresponds to the ligand-binding domain of VirS, adopting an α/β fold with structural similarities to H-NOX domains. Within the VirS structure, SMARt751 is situated in a completely enclosed hydrophobic cavity, where it forms hydrogen bonds with Asn11 and Asn149 as well as van der Waals contacts with various hydrophobic amino acids. Comprehensive structural comparisons within the AraC family of transcriptional regulators are conducted and analyzed to figure out the effects of the SMARt751 binding on the regulatory activity of VirS.
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Affiliation(s)
- Camille Grosse
- Unit of Microbiology, Bioorganic and Macromolecular Chemistry, Department of Research in Drug Development, Faculty of Pharmacy, Université Libre de Bruxelles, Belgium; Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Maud Sigoillot
- Unit of Microbiology, Bioorganic and Macromolecular Chemistry, Department of Research in Drug Development, Faculty of Pharmacy, Université Libre de Bruxelles, Belgium
| | - Véronique Megalizzi
- Unit of Microbiology, Bioorganic and Macromolecular Chemistry, Department of Research in Drug Development, Faculty of Pharmacy, Université Libre de Bruxelles, Belgium
| | - Abdalkarim Tanina
- Unit of Microbiology, Bioorganic and Macromolecular Chemistry, Department of Research in Drug Development, Faculty of Pharmacy, Université Libre de Bruxelles, Belgium
| | - Nicolas Willand
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000 Lille, France
| | - Alain R Baulard
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - René Wintjens
- Unit of Microbiology, Bioorganic and Macromolecular Chemistry, Department of Research in Drug Development, Faculty of Pharmacy, Université Libre de Bruxelles, Belgium.
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Scholl D, Sigoillot M, Overtus M, Martinez RC, Martens C, Wang Y, Pardon E, Laeremans T, Garcia-Pino A, Steyaert J, Sheppard DN, Hendrix J, Govaerts C. A topological switch in CFTR modulates channel activity and sensitivity to unfolding. Nat Chem Biol 2021; 17:989-997. [PMID: 34341587 DOI: 10.1038/s41589-021-00844-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 06/28/2021] [Indexed: 12/25/2022]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) anion channel is essential to maintain fluid homeostasis in key organs. Functional impairment of CFTR due to mutations in the cftr gene leads to cystic fibrosis. Here, we show that the first nucleotide-binding domain (NBD1) of CFTR can spontaneously adopt an alternate conformation that departs from the canonical NBD fold previously observed. Crystallography reveals that this conformation involves a topological reorganization of NBD1. Single-molecule fluorescence resonance energy transfer microscopy shows that the equilibrium between the conformations is regulated by adenosine triphosphate binding. However, under destabilizing conditions, such as the disease-causing mutation F508del, this conformational flexibility enables unfolding of the β-subdomain. Our data indicate that, in wild-type CFTR, this conformational transition of NBD1 regulates channel function, but, in the presence of the F508del mutation, it allows domain misfolding and subsequent protein degradation. Our work provides a framework to design conformation-specific therapeutics to prevent noxious transitions.
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Affiliation(s)
- Daniel Scholl
- SFMB, Université Libre de Bruxelles, Brussels, Belgium
| | | | - Marie Overtus
- SFMB, Université Libre de Bruxelles, Brussels, Belgium
| | | | - Chloé Martens
- SFMB, Université Libre de Bruxelles, Brussels, Belgium
| | - Yiting Wang
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Els Pardon
- VIB-VUB center for Structural Biology, VIB, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Toon Laeremans
- VIB-VUB center for Structural Biology, VIB, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Abel Garcia-Pino
- Cellular and Molecular Microbiology, Université Libre de Bruxelles, Gosselies, Belgium
| | - Jan Steyaert
- VIB-VUB center for Structural Biology, VIB, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Jelle Hendrix
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre and Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.,Molecular Imaging and Photonics, Chemistry Department, KU Leuven, Leuven, Belgium
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Sigoillot M, Brockhoff A, Neiers F, Poirier N, Belloir C, Legrand P, Charron C, Roblin P, Meyerhof W, Briand L. The Crystal Structure of Gurmarin, a Sweet Taste-Suppressing Protein: Identification of the Amino Acid Residues Essential for Inhibition. Chem Senses 2019; 43:635-643. [PMID: 30137256 DOI: 10.1093/chemse/bjy054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Gurmarin is a highly specific sweet taste-suppressing protein in rodents that is isolated from the Indian plant Gymnema sylvestre. Gurmarin consists of 35 amino acid residues containing 3 intramolecular disulfide bridges that form a cystine knot. Here, we report the crystal structure of gurmarin at a 1.45 Å resolution and compare it with previously reported nuclear magnetic resonance solution structures. The atomic structure at this resolution allowed us to identify a very flexible region consisting of hydrophobic residues. Some of these amino acid residues had been identified as a putative binding site for the rat sweet taste receptor in a previous study. By combining alanine-scanning mutagenesis of the gurmarin molecule and a functional cell-based receptor assay, we confirmed that some single point mutations in these positions drastically affect sweet taste receptor inhibition by gurmarin.
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Affiliation(s)
- Maud Sigoillot
- INRA, CNRS, Centre des Sciences du Goût et de l'Alimentation, Université de Bourgogne-Franche Comté, Dijon, France
| | - Anne Brockhoff
- Department of Molecular Genetics, German Institute of Human Nutrition, Potsdam-Rehbruecke, Arthur-Scheunert-Allee, Nuthetal, Germany
| | - Fabrice Neiers
- INRA, CNRS, Centre des Sciences du Goût et de l'Alimentation, Université de Bourgogne-Franche Comté, Dijon, France
| | - Nicolas Poirier
- INRA, CNRS, Centre des Sciences du Goût et de l'Alimentation, Université de Bourgogne-Franche Comté, Dijon, France
| | - Christine Belloir
- INRA, CNRS, Centre des Sciences du Goût et de l'Alimentation, Université de Bourgogne-Franche Comté, Dijon, France
| | - Pierre Legrand
- SOLEIL Synchrotron, L'Orme de Merisiers, Saint-Aubin, Gif-sur-Yvette, France
| | - Christophe Charron
- Ingénierie Moléculaire et Physiopathologie Articulaire, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7365, Université de Lorraine, Biopôle de l'Université de Lorraine, Vandoeuvre-les-Nancy Cedex, France
| | - Pierre Roblin
- SOLEIL Synchrotron, L'Orme de Merisiers, Saint-Aubin, Gif-sur-Yvette, France
| | - Wolfgang Meyerhof
- Department of Molecular Genetics, German Institute of Human Nutrition, Potsdam-Rehbruecke, Arthur-Scheunert-Allee, Nuthetal, Germany
| | - Loïc Briand
- INRA, CNRS, Centre des Sciences du Goût et de l'Alimentation, Université de Bourgogne-Franche Comté, Dijon, France
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4
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Sigoillot M, Overtus M, Grodecka M, Scholl D, Garcia-Pino A, Laeremans T, He L, Pardon E, Hildebrandt E, Urbatsch I, Steyaert J, Riordan JR, Govaerts C. Domain-interface dynamics of CFTR revealed by stabilizing nanobodies. Nat Commun 2019; 10:2636. [PMID: 31201318 PMCID: PMC6572788 DOI: 10.1038/s41467-019-10714-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [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] [Received: 06/13/2018] [Accepted: 05/21/2019] [Indexed: 01/17/2023] Open
Abstract
The leading cause of cystic fibrosis (CF) is the deletion of phenylalanine 508 (F508del) in the first nucleotide-binding domain (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR). The mutation affects the thermodynamic stability of the domain and the integrity of the interface between NBD1 and the transmembrane domain leading to its clearance by the quality control system. Here, we develop nanobodies targeting NBD1 of human CFTR and demonstrate their ability to stabilize both isolated NBD1 and full-length protein. Crystal structures of NBD1-nanobody complexes provide an atomic description of the epitopes and reveal the molecular basis for stabilization. Furthermore, our data uncover a conformation of CFTR, involving detachment of NBD1 from the transmembrane domain, which contrast with the compact assembly observed in cryo-EM structures. This unexpected interface rearrangement is likely to have major relevance for CF pathogenesis but also for the normal function of CFTR and other ABC proteins.
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Affiliation(s)
- Maud Sigoillot
- SFMB, Université Libre de Bruxelles (ULB), CP206/02, Boulevard du Triomphe, building BC, B-1050, Brussels, Belgium
| | - Marie Overtus
- SFMB, Université Libre de Bruxelles (ULB), CP206/02, Boulevard du Triomphe, building BC, B-1050, Brussels, Belgium
| | - Magdalena Grodecka
- SFMB, Université Libre de Bruxelles (ULB), CP206/02, Boulevard du Triomphe, building BC, B-1050, Brussels, Belgium
| | - Daniel Scholl
- SFMB, Université Libre de Bruxelles (ULB), CP206/02, Boulevard du Triomphe, building BC, B-1050, Brussels, Belgium
| | - Abel Garcia-Pino
- Laboratoire de Microbiologie Moléculaire et Cellulaire, ULB CP300, rue des Professeurs Jeener et Brachet 12, B-6041, Charleroi, Belgium
| | - Toon Laeremans
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.,VIB-VUB center for Structural Biology, VIB, Pleinlaan 2, B-1050, Brussels, Belgium
| | - Lihua He
- Department of Biochemistry and Biophysics and Cystic Fibrosis Center, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.,VIB-VUB center for Structural Biology, VIB, Pleinlaan 2, B-1050, Brussels, Belgium
| | - Ellen Hildebrandt
- Department of Cell Biology and Biochemistry and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street, Stop 6540, Lubbock, TX, 79430, USA
| | - Ina Urbatsch
- Department of Cell Biology and Biochemistry and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street, Stop 6540, Lubbock, TX, 79430, USA
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.,VIB-VUB center for Structural Biology, VIB, Pleinlaan 2, B-1050, Brussels, Belgium
| | - John R Riordan
- Department of Biochemistry and Biophysics and Cystic Fibrosis Center, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Cedric Govaerts
- SFMB, Université Libre de Bruxelles (ULB), CP206/02, Boulevard du Triomphe, building BC, B-1050, Brussels, Belgium.
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Sigoillot M, Brockhoff A, Meyerhof W, Briand L. Sweet-taste-suppressing compounds: current knowledge and perspectives of application. Appl Microbiol Biotechnol 2012. [PMID: 22983596 DOI: 10.1007/s00253‐012‐4387‐3] [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] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Sweet-tasting compounds are recognized by a heterodimeric receptor composed of the taste receptor, type 1, members 2 (T1R2) and 3 (T1R3) located in the mouth. This receptor is also expressed in the gut where it is involved in intestinal absorption, metabolic regulation, and glucose homeostasis. These metabolic functions make the sweet taste receptor a potential novel therapeutic target for the treatment of obesity and related metabolic dysfunctions such as diabetes. Existing sweet taste inhibitors or blockers that are still in development would constitute promising therapeutic agents. In this review, we will summarize the current knowledge of sweet taste inhibitors, including a sweet-taste-suppressing protein named gurmarin, which is only active on rodent sweet taste receptors but not on that of humans. In addition, their potential applications as therapeutic tools are discussed.
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Affiliation(s)
- Maud Sigoillot
- Centre des Sciences du Goût et de l'Alimentation, UMR-1324 INRA, UMR-6265 CNRS, Université de Bourgogne, 21000, Dijon, France
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Sigoillot M, Brockhoff A, Meyerhof W, Briand L. Sweet-taste-suppressing compounds: current knowledge and perspectives of application. Appl Microbiol Biotechnol 2012; 96:619-30. [PMID: 22983596 DOI: 10.1007/s00253-012-4387-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/20/2012] [Accepted: 08/21/2012] [Indexed: 01/07/2023]
Abstract
Sweet-tasting compounds are recognized by a heterodimeric receptor composed of the taste receptor, type 1, members 2 (T1R2) and 3 (T1R3) located in the mouth. This receptor is also expressed in the gut where it is involved in intestinal absorption, metabolic regulation, and glucose homeostasis. These metabolic functions make the sweet taste receptor a potential novel therapeutic target for the treatment of obesity and related metabolic dysfunctions such as diabetes. Existing sweet taste inhibitors or blockers that are still in development would constitute promising therapeutic agents. In this review, we will summarize the current knowledge of sweet taste inhibitors, including a sweet-taste-suppressing protein named gurmarin, which is only active on rodent sweet taste receptors but not on that of humans. In addition, their potential applications as therapeutic tools are discussed.
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Affiliation(s)
- Maud Sigoillot
- Centre des Sciences du Goût et de l'Alimentation, UMR-1324 INRA, UMR-6265 CNRS, Université de Bourgogne, 21000, Dijon, France
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Maîtrepierre E, Sigoillot M, Le Pessot L, Briand L. An efficient Escherichia coli expression system for the production of a functional N-terminal domain of the T1R3 taste receptor. Bioengineered 2012; 4:25-9. [PMID: 22909933 PMCID: PMC3566016 DOI: 10.4161/bioe.21877] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [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] [Indexed: 11/19/2022] Open
Abstract
Sweet taste is mediated by a dimeric receptor composed of two distinct subunits, T1R2 and T1R3, whereas the T1R1/T1R3 receptor is involved in umami taste perception. The T1R1, T1R2, and T1R3 subunits are members of the small family of class C G protein-coupled receptors (GPCRs). The members of this family are characterized by a large N-terminal domain (NTD), which is structurally similar to bacterial periplasmic-binding proteins and contains the primary ligand-binding site. In a recent study, we described a strategy to produce a functional dimeric human T1R3-NTD. Although the protein was expressed as inclusion bodies (IBs) using the Escherichia coli system, the conditions for the refolding of functional hT1R3-NTD were determined using a fractional factorial screen coupled to a binding assay. Here, we report that this refolding strategy can be used to produce T1R1- and T1R2-NTDs in large quantities. We also discuss that our findings could be more generally applicable to other class C GPCR-NTDs, including the γ-aminobutyric acid type B receptor (GABABR), the extracellular calcium-sensing receptor (CaSR) and the large family of pheromone (V2R) orphan receptors.
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Affiliation(s)
- Elodie Maîtrepierre
- Centre des Sciences du Goût et de l'Alimentation, UMR-1324 INRA, UMR-6265 CNRS, Université de Bourgogne, 21000 Dijon, France
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Maîtrepierre E, Sigoillot M, Le Pessot L, Briand L. Recombinant expression, in vitro refolding, and biophysical characterization of the N-terminal domain of T1R3 taste receptor. Protein Expr Purif 2012; 83:75-83. [PMID: 22450161 DOI: 10.1016/j.pep.2012.03.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 02/28/2012] [Accepted: 03/12/2012] [Indexed: 11/19/2022]
Abstract
The sweet taste receptor is a heterodimeric receptor composed of the T1R2 and T1R3 subunits, while T1R1 and T1R3 assemble to form the umami taste receptor. T1R receptors belong to the family of class C G-protein coupled receptors (GPCRs). In addition to a transmembrane heptahelical domain, class C GPCRs have a large extracellular N-terminal domain (NTD), which is the primary ligand-binding site. The T1R2 and T1R1 subunits have been shown to be responsible for ligand binding, via their NTDs. However, little is known about the contribution of T1R3-NTD to receptor functions. To enable biophysical characterization, we overexpressed the human NTD of T1R3 (hT1R3-NTD) using Escherichia coli in the form of inclusion bodies. Using a fractional factorial screen coupled to a functional assay, conditions were determined for the refolding of hT1R3-NTD. Far-UV circular dichroism spectroscopic studies revealed that hT1R3-NTD was well refolded. Using size-exclusion chromatography, we found that the refolded protein behaves as a dimer. Ligand binding quantified by tryptophan fluorescence quenching and microcalorimetry showed that hT1R3-NTD is functional and capable of binding sucralose with an affinity in the millimolar range. This study also provides a strategy to produce functional hT1R3-NTD by heterologous expression in E. coli; this is a prerequisite for structural determination and functional analysis of ligand-binding regions of other class C GPCRs.
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Affiliation(s)
- Elodie Maîtrepierre
- Centre des Sciences du Goût et de l'Alimentation, UMR6265 CNRS, UMR1324 INRA, Université de Bourgogne, F-21000 Dijon, France
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Sigoillot M, Brockhoff A, Lescop E, Poirier N, Meyerhof W, Briand L. Optimization of the production of gurmarin, a sweet-taste-suppressing protein, secreted by the methylotrophic yeast Pichia pastoris. Appl Microbiol Biotechnol 2012; 96:1253-63. [PMID: 22307499 DOI: 10.1007/s00253-012-3897-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 01/05/2012] [Accepted: 01/09/2012] [Indexed: 10/14/2022]
Abstract
Gurmarin, a 35-residue polypeptide, is known to selectively inhibit responses to sweet substances in rodents without affecting responses to other basic taste stimuli, such as NaCl, HCl, and quinine. Here, we report the heterologous expression of gurmarin using the methylotrophic yeast Pichia pastoris. Gurmarin was secreted into the buffered minimal medium using the α-factor preprosequence without the EAEA spacer peptide of Saccharomyces cerevisiae and was under the control of the methanol-inducible alcohol oxidase promoter. We found that gurmarin accumulated in the yeast culture medium reaching 5 mg per liter of culture over an expression period of 4 days. To compare the production level and the signal peptide processing, the N-terminal amino acid of gurmarin was substituted by a glutamic acid residue. This construct resulted in a 6-fold increase in the level of gurmarin secretion leading to 30 mg of purified protein per liter of culture. Purified recombinant gurmarin resulting from both constructs was characterized using mass spectrometry. Circular dichroism and NMR spectroscopy revealed that recombinant gurmarin was properly folded and had secondary and tertiary structures. We also confirmed its capability to inhibit the rat heterodimeric sweet taste T1R2/T1R3 receptor by functional expression in human embryonic kidney HEK293T cells. The high level of fully active gurmarin obtained in P. pastoris makes this expression system attractive for fermentor growth and pharmacological investigations of taste receptor and gurmarin functions.
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Affiliation(s)
- Maud Sigoillot
- Centre des Sciences du Goût et de l'Alimentation, UMR-6265 CNRS, UMR-1324 INRA, Université de Bourgogne, 21000, Dijon, France
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Raliou M, Grauso M, Hoffmann B, Schlegel-Le-Poupon C, Nespoulous C, Debat H, Belloir C, Wiencis A, Sigoillot M, Preet Bano S, Trotier D, Pernollet JC, Montmayeur JP, Faurion A, Briand L. Human Genetic Polymorphisms in T1R1 and T1R3 Taste Receptor Subunits Affect Their Function. Chem Senses 2011; 36:527-37. [DOI: 10.1093/chemse/bjr014] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [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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Thiebaud N, Sigoillot M, Chevalier J, Artur Y, Heydel JM, Le Bon AM. Effects of typical inducers on olfactory xenobiotic-metabolizing enzyme, transporter, and transcription factor expression in rats. Drug Metab Dispos 2010; 38:1865-75. [PMID: 20639433 DOI: 10.1124/dmd.110.035014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [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
Several xenobiotic-metabolizing enzymes (XMEs) have been identified in the olfactory mucosa (OM) of mammals. However, the molecular mechanisms underlying the regulation of these enzymes have been little explored. In particular, information on the expression of the transcriptional factors in this tissue is quite limited. The aim of the present study was to examine the impact of five typical inducers, Aroclor 1254, 3-methylcholanthrene, dexamethasone, phenobarbital, and ethoxyquin, on the activities and mRNA expression of several XMEs in the OM and in the liver of rats. We also evaluated the effects of these treatments on the mRNA expression of transcription factors and transporters. On the whole, the intensities of the effects were lower in the OM than in the liver. Dexamethasone was found to be the most efficient treatment in the OM. Dexamethasone induced the transcription of several olfactory phase I, II, and III genes [such as cytochromes P450 2A3 and 3A9, UDP-glucuronosyltransferase (UGT) 2A1, and multidrug resistance-related protein type 1] and increased UGT activities. We observed that dexamethasone up-regulated sulfotransferase 1C1 expression in the OM but down-regulated it in the liver. Aroclor and ethoxyquin induced the gene expression of CYP1A and quinone reductase, respectively, in the OM. The transcription factors aryl hydrocarbon receptor, nuclear factor E2-related factor 2 (Nrf2), peroxisome proliferator-activated receptor α, pregnane X receptor, and glucocorticoid receptor were detected in the OM, but no constitutive androstane receptor expression was observed. Dexamethasone and Aroclor enhanced olfactory Nrf2 expression. These results demonstrate that olfactory XME can be modulated by chemicals and that the mechanisms involved in the regulation of these enzymes are tissue-specific.
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Affiliation(s)
- Nicolas Thiebaud
- Centre des Sciences du Goût et de l’Alimentation, UMR 1324 INRA, UMR 6265 CNRS, Université de Bourgogne, Agrosup Dijon, 17 rue Sully, Dijon, France
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