1
|
Jin SB, Kim HA, Shin JA, Jung NH, Park SY, Hong S, Kong KH. Recombinant expression and tryptophan-assisted analysis of human sweet taste receptor T1R3's extracellular domain in sweetener interaction studies. Prep Biochem Biotechnol 2024:1-8. [PMID: 38578840 DOI: 10.1080/10826068.2024.2336985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Abstract
The human palate can discern multiple tastes; however, it predominantly perceives five fundamental flavors: sweetness, saltiness, sourness, bitterness, and umami. Sweetness is primarily mediated through the sweet taste receptor, a membrane-bound heterodimeric structure comprising T1R2-T1R3. However, unraveling the structural and mechanistic intricacies of the sweet taste receptor has proven challenging. This study aimed to address this knowledge gap by expressing an extracellular N-terminal domain encompassing the cysteine-rich domain of human hT1R3 (hT1R3-TMD) in Escherichia coli. The expressed protein was obtained as inclusion bodies, purified by metal affinity chromatography, and refolded using the dilution-refolding method. Through rigorous analysis, we confirmed the successful refolding of hT1R3-TMD and elucidated its structural characteristics using circular dichroism spectroscopy. Notably, the refolded protein was found to exist as either a monomer or a dimer, depending on its concentration. A tryptophan fluorescence quenching assay revealed that the dissociation constants for sucrose, sucralose, and brazzein were >9500 μM, 2380 μM and 14.3 μM, respectively. Our findings highlight the utility of this E. coli expression system for producing functional hT1R3-TMD for investigations and demonstrate the efficacy of the tryptophan fluorescence quenching assay in revealing complex interactions between sweet taste receptors and various sweeteners.
Collapse
Affiliation(s)
- Soo-Bin Jin
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, Seoul, Korea
| | - Hyun-A Kim
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, Seoul, Korea
| | - Ji-Ae Shin
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, Seoul, Korea
| | - Na-Hee Jung
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, Seoul, Korea
| | - Seo-Young Park
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, Seoul, Korea
| | - Sungguan Hong
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, Seoul, Korea
| | - Kwang-Hoon Kong
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, Seoul, Korea
| |
Collapse
|
2
|
Zhang N, Cui Z, Li M, Fan Y, Liu J, Wang W, Zhang Y, Liu Y. Typical Umami Ligand-Induced Binding Interaction and Conformational Change of T1R1-VFT. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:11652-11666. [PMID: 36098631 DOI: 10.1021/acs.jafc.2c05559] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Umami taste receptor type 1 member 1/3 (T1R1/T1R3) heterodimer has multiple ligand-binding sites, most of which are located in T1R1-Venus flytrap domain (T1R1-VFT). However, the critical binding process of T1R1-VFT/umami ligands remains largely unknown. Herein, T1R1-VFT was prepared with a sufficient amount and functional activity, and its binding characteristics with typical umami molecules (monosodium l-glutamate, disodium succinate, beefy meaty peptide, and inosine-5'-monophosphate) were explored via multispectroscopic techniques and molecular dynamics simulation. The results showed that, driven mainly by hydrogen bond, van der Waals forces, and electrostatic interactions, T1R1-VFT bound to umami compound at 1:1 (stoichiometric interaction) and formed T1R1-VFT/ligand complex (static fluorescence quenching) with a weak binding affinity (Ka values: 252 ± 19 to 1169 ± 112 M-1). The binding process was spontaneous and exothermic (ΔG, -17.72 to -14.26 kJ mol-1; ΔH, -23.86 to -12.11 kJ mol-1) and induced conformational changes of T1R1-VFT, which was mainly reflected in slight unfolding of α-helix (Δα-helix < 0) and polypeptide chain backbone structure. Meanwhile, the binding of the four ligands stabilized the active conformation of the T1R1-VFT pocket. This work provides insight into the binding interaction between T1R1-VFT/umami ligands and improves understanding of how umami receptor recognizes specific ligand molecules.
Collapse
Affiliation(s)
- Ninglong Zhang
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Zhiyong Cui
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Mingyang Li
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Yuxia Fan
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Jing Liu
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255049, Shandong Province, P. R. China
| | - Wenli Wang
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Yin Zhang
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu 610106, P. R. China
| | - Yuan Liu
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| |
Collapse
|
3
|
Laffitte A, Belloir C, Neiers F, Briand L. Functional Characterization of the Venus Flytrap Domain of the Human TAS1R2 Sweet Taste Receptor. Int J Mol Sci 2022; 23:ijms23169216. [PMID: 36012481 PMCID: PMC9409066 DOI: 10.3390/ijms23169216] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 11/16/2022] Open
Abstract
The human sweet taste receptor is a heterodimeric receptor composed of two distinct G-protein-coupled receptors (GPCRs), TAS1R2 and TAS1R3. The TAS1R2 and TAS1R3 subunits are members of a small family of class C GPCRs whose members share the same architecture, comprising a Venus Flytrap (VFT) module linked to the seven transmembrane domains (TMDs) by a short cysteine-rich region (CRR). The VFT module of TAS1R2 contains the primary binding site for most of the sweet-tasting compounds, including natural sugars and artificial and natural sweeteners. However, cellular assays, molecular docking and site-directed mutagenesis studies have revealed that the VFT, CRR and TMD of TAS1R3 interact with some sweeteners, including the sweet-tasting protein brazzein. The aim of this study was to better understand the contribution of TAS1R2-VFT in the binding of sweet stimuli. To achieve this, we heterologously expressed human TAS1R2-VFT (hTAS1R2-VFT) in Escherichia coli. Circular dichroism spectroscopic studies revealed that hTAS1R2-VFT was properly folded with evidence of secondary structures. Using size-exclusion chromatography coupled with light scattering, we found that hTAS1R2-VFT behaves as a monomer. Ligand binding quantified by intrinsic tryptophan fluorescence showed that hTAS1R2-VFT is capable of binding sweet stimuli with Kd values, in agreement with physiological detection. Furthermore, we investigated whether the impact of point mutations, already shown to have deleterious effects on cellular assays, could impact the ability of hTAS1R2-VFT to bind sweet ligands. As expected, the ligand affinities of hTAS1R2-VFT were drastically reduced through the introduction of single amino acid substitutions (D278A and E382A) known to abolish the response of the full-length TAS1R2/TAS1R3 receptor. This study demonstrates the feasibility of producing milligram quantities of hTAS1R2-VFT to further characterize the mechanism of binding interaction and perform structural studies.
Collapse
|
4
|
Zhang C, Miao Y, Feng Y, Wang J, Tian Z, Dong J, Gao B, Zhang L. Umami polypeptide detection system targeting the human T1R1 receptor and its taste-presenting mechanism. Biomaterials 2022; 287:121660. [PMID: 35792387 DOI: 10.1016/j.biomaterials.2022.121660] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 06/24/2022] [Indexed: 01/30/2023]
Abstract
Umami is one of five basic tastes, the elucidation of its mechanism by the study of the interaction between umami polypeptides and hT1R1 umami receptors is of great significance. However, research on umami peptides targeting human T1R1 receptors is lacking, and the molecular mechanism remains elusive. Here, we successfully established a system to detect umami peptides targeting human T1R1 receptors by fluorescence spectroscopy, Surface Plasmon Resonance (SPR) and computational simulation. The sensory evaluation, calculated Kd value, and experimental affinity results between the four selected umami peptides (GRVSNCAA, KGDEESLA, KGGGGP, and TGDPEK) and glutamate were tested using this system, and all matched well. The maximum Ka value of GRVSNCAA was 479.55 M-1, and the minimum affinity of TGDPEK was 2.67 M-1. Computational simulations showed that the different peptide binding sites in the hT1R1 binding pocket occupied due to conformational changes are important factors for different taste thresholds, and that peptide hydrophobicity plays an important role in regulating affinity. Thus, our study enables rapid screening of high-intensity umami peptides and the development of T1R1 receptor-based umami detection sensors.
Collapse
Affiliation(s)
- Chuanxi Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China; School of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China; Department of Micro/Nano Electronics, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai , 200240, China
| | - Yulu Miao
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
| | - Yinghui Feng
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
| | - Jiawei Wang
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China; School of Health Science and Engineering, University of Shanghai for Science and Tecchnology, Shanghai, 200093, China
| | - Zhuoli Tian
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
| | - Juan Dong
- School of Food Science and Technology, Shihezi University, Shihezi, 832000, China
| | - Bei Gao
- School of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
| | - Lujia Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China; NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, 200062, China.
| |
Collapse
|
5
|
Biophysical and functional characterization of the human TAS1R2 sweet taste receptor overexpressed in a HEK293S inducible cell line. Sci Rep 2021; 11:22238. [PMID: 34782704 PMCID: PMC8593021 DOI: 10.1038/s41598-021-01731-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 11/01/2021] [Indexed: 01/02/2023] Open
Abstract
Sweet taste perception is mediated by a heterodimeric receptor formed by the assembly of the TAS1R2 and TAS1R3 subunits. TAS1R2 and TAS1R3 are class C G-protein-coupled receptors whose members share a common topology, including a large extracellular N-terminal domain (NTD) linked to a seven transmembrane domain (TMD) by a cysteine-rich domain. TAS1R2-NTD contains the primary binding site for sweet compounds, including natural sugars and high-potency sweeteners, whereas the TAS1R2-TMD has been shown to bind a limited number of sweet tasting compounds. To understand the molecular mechanisms governing receptor–ligand interactions, we overexpressed the human TAS1R2 (hTAS1R2) in a stable tetracycline-inducible HEK293S cell line and purified the detergent-solubilized receptor. Circular dichroism spectroscopic studies revealed that hTAS1R2 was properly folded with evidence of secondary structures. Using size exclusion chromatography coupled to light scattering, we found that the hTAS1R2 subunit is a dimer. Ligand binding properties were quantified by intrinsic tryptophan fluorescence. Due to technical limitations, natural sugars have not been tested. However, we showed that hTAS1R2 is capable of binding high potency sweeteners with Kd values that are in agreement with physiological detection. This study offers a new experimental strategy to identify new sweeteners or taste modulators that act on the hTAS1R2 and is a prerequisite for structural query and biophysical studies.
Collapse
|
6
|
Current Progress in Understanding the Structure and Function of Sweet Taste Receptor. J Mol Neurosci 2020; 71:234-244. [PMID: 32607758 DOI: 10.1007/s12031-020-01642-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 06/19/2020] [Indexed: 10/24/2022]
Abstract
The sweet taste receptor, which was identified approximately 20 years ago, mediates sweet taste recognition in humans and other vertebrates. With the development of genomics, metabonomics, structural biology, evolutionary biology, physiology, and neuroscience, as well as technical advances in these areas, our understanding of this important protein has resulted in substantial progress. This article reviews the structure, function, genetics, and evolution of the sweet taste receptor and offers meaningful insights into this G protein-coupled receptor, which may be helpful guidances for personalized feeding, diet, and medicine. Prospective directions for research on sweet taste receptors have also been proposed.
Collapse
|
7
|
Belloir C, Savistchenko J, Neiers F, Taylor AJ, McGrane S, Briand L. Biophysical and functional characterization of the N-terminal domain of the cat T1R1 umami taste receptor expressed in Escherichia coli. PLoS One 2017; 12:e0187051. [PMID: 29084235 PMCID: PMC5662223 DOI: 10.1371/journal.pone.0187051] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 10/12/2017] [Indexed: 11/21/2022] Open
Abstract
Umami taste perception is mediated by the heterodimeric G-protein coupled receptors (GPCRs), formed by the assembly of T1R1 and T1R3 subunits. T1R1 and T1R3 subunits are class C GPCRs whose members share common structural homologies including a long N-terminal domain (NTD) linked to a seven transmembrane domain by a short cysteine-rich region. The NTD of the T1R1 subunit contains the primary binding site for umami stimuli, such as L-glutamate (L-Glu) for humans. Inosine-5’-monophosphate (IMP) binds at a location close to the opening of the T1R1-NTD “flytrap”, thus creating the observed synergistic response between L-Glu and IMP. T1R1/T1R3 binding studies have revealed species-dependent differences. While human T1R1/T1R3 is activated specifically by L-Glu, the T1R1/T1R3 in other species is a broadly tuned receptor, sensitive to a range of L-amino acids. Because domestic cats are obligate carnivores, they display strong preferences for some specific amino acids. To better understand the structural basis of umami stimuli recognition by non-human taste receptors, we measured the binding of selected amino acids to cat T1R1/T1R3 (cT1R1/cT1R3) umami taste receptor. For this purpose, we expressed cT1R1-NTD in bacteria as inclusion bodies. After purification, refolding of the protein was achieved. Circular dichroism spectroscopic studies revealed that cT1R1-NTD was well renatured with evidence of secondary structures. Using size-exclusion chromatography coupled to light scattering, we found that the cT1R1-NTD behaves as a monomer. Ligand binding quantified by intrinsic tryptophan fluorescence showed that cT1R1-NTD is capable of binding L-amino acids with Kd values in the micromolar range. We demonstrated that IMP potentiates L-amino acid binding onto renatured cT1R1-NTD. Interestingly, our results revealed that IMP binds the extracellular domain in the absence of L-amino acids. Thus, this study demonstrates that the feasibility to produce milligram quantities of cT1R1-NTD for functional and structural studies.
Collapse
Affiliation(s)
- Christine Belloir
- Centre des Sciences du Goût et de l'Alimentation, INRA, CNRS, Bourgogne Franche-Comté University, AgroSup Dijon, Dijon, France
| | - Jimmy Savistchenko
- Centre des Sciences du Goût et de l'Alimentation, INRA, CNRS, Bourgogne Franche-Comté University, AgroSup Dijon, Dijon, France
| | - Fabrice Neiers
- Centre des Sciences du Goût et de l'Alimentation, INRA, CNRS, Bourgogne Franche-Comté University, AgroSup Dijon, Dijon, France
| | - Andrew J. Taylor
- WALTHAM Centre for Pet Nutrition, Melton Mowbray, Leicestershire, Great Britain
| | - Scott McGrane
- WALTHAM Centre for Pet Nutrition, Melton Mowbray, Leicestershire, Great Britain
| | - Loïc Briand
- Centre des Sciences du Goût et de l'Alimentation, INRA, CNRS, Bourgogne Franche-Comté University, AgroSup Dijon, Dijon, France
- * E-mail:
| |
Collapse
|
8
|
Briand L, Marcion G, Kriznik A, Heydel JM, Artur Y, Garrido C, Seigneuric R, Neiers F. A self-inducible heterologous protein expression system in Escherichia coli. Sci Rep 2016; 6:33037. [PMID: 27611846 PMCID: PMC5017159 DOI: 10.1038/srep33037] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 08/16/2016] [Indexed: 12/24/2022] Open
Abstract
Escherichia coli is an important experimental, medical and industrial cell factory for recombinant protein production. The inducible lac promoter is one of the most commonly used promoters for heterologous protein expression in E. coli. Isopropyl-β-D-thiogalactoside (IPTG) is currently the most efficient molecular inducer for regulating this promoter’s transcriptional activity. However, limitations have been observed in large-scale and microplate production, including toxicity, cost and culture monitoring. Here, we report the novel SILEX (Self-InducibLe Expression) system, which is a convenient, cost-effective alternative that does not require cell density monitoring or IPTG induction. We demonstrate the broad utility of the presented self-inducible method for a panel of diverse proteins produced in large amounts. The SILEX system is compatible with all classical culture media and growth temperatures and allows protein expression modulation. Importantly, the SILEX system is proven to be efficient for protein expression screening on a microplate scale.
Collapse
Affiliation(s)
- L Briand
- Centre des Sciences du Goût et de l'Alimentation, INRA, Université de Bourgogne Franche-Comté, F-21000 Dijon, France
| | - G Marcion
- Université de Bourgogne Franche-Comté, Dijon, France.,INSERM, UMR 866, 7 blvd Jeanne d'Arc, 21000 Dijon, France
| | - A Kriznik
- UMR 7365 CNRS-Université de Lorraine IMoPA, 9 Avenue de la Forêt de Haye 54505 Vandoeuvre Les Nancy
| | - J M Heydel
- Centre des Sciences du Goût et de l'Alimentation, INRA, Université de Bourgogne Franche-Comté, F-21000 Dijon, France.,Université de Bourgogne Franche-Comté, Dijon, France
| | - Y Artur
- Centre des Sciences du Goût et de l'Alimentation, INRA, Université de Bourgogne Franche-Comté, F-21000 Dijon, France.,Université de Bourgogne Franche-Comté, Dijon, France
| | - C Garrido
- Université de Bourgogne Franche-Comté, Dijon, France.,INSERM, UMR 866, 7 blvd Jeanne d'Arc, 21000 Dijon, France.,Anticancer Center Georges François Leclerc, Dijon, France
| | - R Seigneuric
- Université de Bourgogne Franche-Comté, Dijon, France.,INSERM, UMR 866, 7 blvd Jeanne d'Arc, 21000 Dijon, France
| | - F Neiers
- Centre des Sciences du Goût et de l'Alimentation, INRA, Université de Bourgogne Franche-Comté, F-21000 Dijon, France.,Université de Bourgogne Franche-Comté, Dijon, France
| |
Collapse
|