1
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Masuda T, Suzuki M, Yamasaki M, Mikami B. Subatomic structure of orthorhombic thaumatin at 0.89 Å reveals that highly flexible conformations are crucial for thaumatin sweetness. Biochem Biophys Res Commun 2024; 703:149601. [PMID: 38364680 DOI: 10.1016/j.bbrc.2024.149601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 02/18/2024]
Abstract
Thaumatin is a sweet-tasting protein that elicits a sweet taste at a threshold of approximately 50 nM. Structure-sweetness relationships in thaumatin suggest that the basicity of two amino acids residues, Arg82 and Lys67, are particularly responsible for sweetness. Using tetragonal crystals, our structural analysis suggested that flexible sidechain conformations of these two residues play an important role in sweetness. However, in tetragonal crystals, Arg82 is adjacent to symmetry-related residues, and its flexibility is relatively restrained by the crystal packing. To reduce and diminish these symmetry-related effects, orthorhombic crystals were prepared, and their structures were successfully determined at a resolution of 0.89 Å. Within the orthorhombic lattice, two alternative conformations were more clearly visible at Lys67 than in a tetragonal system. Interestingly, for the first time, three alternative conformations at Arg82 were only found in an orthorhombic system. These results suggest the importance of flexible conformations in sweetness determinants. Such subtle structural variations might serve to adjust the complementarity of the electrostatic potentials of sweet receptors, thereby eliciting the potent sweet taste of thaumatin.
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Affiliation(s)
- Tetsuya Masuda
- Department of Food Sciences and Human Nutrition, Faculty of Agriculture, Ryukoku University, 1-5 Yokotani, Seta Oe-cho, Otsu, Shiga, 520-2194, Japan; Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
| | - Mamoru Suzuki
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masayuki Yamasaki
- Department of Food Sciences and Human Nutrition, Faculty of Agriculture, Ryukoku University, 1-5 Yokotani, Seta Oe-cho, Otsu, Shiga, 520-2194, Japan
| | - Bunzo Mikami
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan; Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
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2
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Yuan Y, Yiasmin MN, Tristanto NA, Chen Y, Liu Y, Guan S, Wang Z, Hua X. Computational simulations on the taste mechanism of steviol glycosides based on their interactions with receptor proteins. Int J Biol Macromol 2024; 255:128110. [PMID: 37981277 DOI: 10.1016/j.ijbiomac.2023.128110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/13/2023] [Accepted: 11/13/2023] [Indexed: 11/21/2023]
Abstract
Steviol glycoside (SG) is a potential natural sugar substitute. The taste of various SG structures differ significantly, while their mechanism has not been thoroughly investigated. To investigate the taste mechanism, molecular docking simulations of SGs with sweet taste receptor TAS1R2 and bitter taste receptor TAS2R4 were conducted. The result suggested that four flexible coils (regions) in TAS1R2 constructed a geometry open pocket in space responsible for the binding of sweeteners. Amino acids that form hydrogen bonds with sweeteners are located in different receptor regions. In bitterness simulation, fewer hydrogen bonds were formed with the increased size of SG molecules. Particularly, there was no interaction between RM and TAS2R4 due to its size, which explains the non-bitterness of RM. Molecular dynamics simulations further indicated that the number of hydrogen bonds between SGs and TAS1R2 was maintained during a simulation time of 50 ns, while sucrose was gradually released from the binding site, leading to the break of interaction. Conclusively, the high sweetness intensity of SG can be attributed to its durative concurrent interaction with the receptor's binding site, and such behavior was determined by the structure feature of SG.
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Affiliation(s)
- Yuying Yuan
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Mst Nushrat Yiasmin
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | | | - Yujie Chen
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Jiangsu Sevtia Biotechnology Co., Ltd., Wuxi 214181, China
| | - Yaxian Liu
- Department of Biotechnology and Enzyme Science, University of Hohenheim, Institute of Food Science and Biotechnology, Garbenstr. 25, 70599 Stuttgart, Germany
| | - Shuyi Guan
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Zijie Wang
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xiao Hua
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
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3
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Dubovski N, Fierro F, Margulis E, Ben Shoshan-Galeczki Y, Peri L, Niv MY. Taste GPCRs and their ligands. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 193:177-193. [PMID: 36357077 DOI: 10.1016/bs.pmbts.2022.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Taste GPCRs are expressed in taste buds on the tongue and play a key role in food choice and consumption. They are also expressed extra-orally, with various physiological roles that are currently under study. Unraveling the roles of these receptors relies on the knowledge of their ligands. Combining sensory, cell-based and computational approaches enabled the discovery of numerous agonists and several antagonists. Here we provide a short overview of taste receptor families, main recent methods for ligands discovery, and current sources of information about known ligands. The future directions that are likely to impact the taste GPCR field include focus on ligand interactions with naturally occurring polymorphisms, as well as harnessing the power of CryoEM and of multiple signaling readout techniques.
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Affiliation(s)
- Nitzan Dubovski
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Fabrizio Fierro
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Eitan Margulis
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yaron Ben Shoshan-Galeczki
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Lior Peri
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Masha Y Niv
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
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4
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Yu J, Xie J, Xie H, Hu Q, Wu Z, Cai X, Guo Z, Lin J, Han L, Zhang D. Strategies for Taste Masking of Orodispersible Dosage Forms: Time, Concentration, and Perception. Mol Pharm 2022; 19:3007-3025. [PMID: 35848076 DOI: 10.1021/acs.molpharmaceut.2c00199] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Orodispersible dosage forms, characterized as quick dissolving and swallowing without water, have recently gained great attention from the pharmaceutical industry, as these forms can satisfy the needs of children, the elderly, and patients suffering from mental illnesses. However, poor taste by thorough exposure of the drugs' dissolution in the oral cavity hinders the effectiveness of the orodispersible dosage forms. To bridge this gap, we put forward three taste-masking strategies with respect to the intensity of time, concentration, and perception. We further investigated the raw material processing, the composition of auxiliary material, formulation techniques, and process control in each strategy and drew conclusions about their effects on taste masking.
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Affiliation(s)
- Ji Yu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
| | - Jin Xie
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
| | - Huijuan Xie
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
| | - Qi Hu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
| | - Zhenfeng Wu
- Key Laboratory of Modern Preparation of Chinese Medicine, Ministry of Education, Jiangxi University of Chinese Medicine, Nanchang 330004, PR China
| | - Xinfu Cai
- Sichuan Guangda Pharmaceutical Co., Ltd., Pengzhou 611930, PR China
| | - Zhiping Guo
- Sichuan Houde Pharmaceutical Technology Co., Ltd., Chengdu 610041, PR China
| | - Junzhi Lin
- TCM Regulating Metabolic Diseases Key Laboratory of Sichuan Province, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610072, PR China
| | - Li Han
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
| | - Dingkun Zhang
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
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5
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Jang J, Kim SK, Guthrie B, Goddard WA. Synergic Effects in the Activation of the Sweet Receptor GPCR Heterodimer for Various Sweeteners Predicted Using Molecular Metadynamics Simulations. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:12250-12261. [PMID: 34613740 DOI: 10.1021/acs.jafc.1c03779] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The sweet taste is elicited by activation of the TAS1R2/1R3 heterodimer G protein-coupled receptor. This is a therapeutic target for treatment of obesity and metabolic dysfunctions. Sweetener blends provide attractive strategies to lower the sugar level while preserving the attractive taste of food. To understand the synergic effect of various sweetener blend combinations of artificial and natural sweeteners, we carried out our molecular dynamics studies using predicted structures of the TAS1R2/1R3 heterodimer and predicted structures for the sweeteners. We used as a measure of activation the intracellular ionic lock distance between transmembrane helices 3 and 6 of TAS1R3. We find that full synergic combinations [rebaudioside A (Reb-A)/acesulfame K and Reb-A/sucralose] and partial synergic combinations (sucralose/acesulfame K) show significantly more negative changes in the free energy compared to single-ligand cases, while a pair known to be suppressive (saccharin and acesulfame K) shows significantly less changes than for the single-ligand case. This study provides an atomistic understanding of the mechanism for synergy and identifies new combinations of sweeteners to reduce the caloric content for treating diseases.
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Affiliation(s)
- Jaewan Jang
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
| | - Soo-Kyung Kim
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
| | - Brian Guthrie
- Cargill Global Core Research, Wayzata, Minnesota 55391, United States
| | - William A Goddard
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
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6
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Jiang J, Liu S, Qi L, Wei Q, Shi F. Activation of Ovarian Taste Receptors Inhibits Progesterone Production Potentially via NO/cGMP and Apoptotic Signaling. Endocrinology 2021; 162:6052298. [PMID: 33367902 DOI: 10.1210/endocr/bqaa240] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Indexed: 12/25/2022]
Abstract
Taste receptors are not only expressed in the taste buds, but also in other nongustatory tissues, including the reproductive system. Taste receptors can be activated by various tastants, thereby exerting relatively physiologic functions. The aim of this study was to investigate the effects and potential mechanisms underlying ovarian taste receptor activation on progesterone production using saccharin sodium as the receptor agonist in a pseudopregnant rat model. Taste 1 receptor member 2 (TAS1R2) and taste 2 receptor member 31 (TAS2R31) were demonstrated to be abundantly expressed in the corpora lutea of rats, and intraperitoneal injection of saccharin sodium can activate both of them and initiate their downstream signaling cascades. The activation of these ovarian taste receptors promoted nitric oxide (NO) production via endothelial nitric oxide synthase (eNOS). NO production then increased ovarian cyclic guanosine 3',5'-monophosphate (cGMP) levels, which, in turn, decreased ovarian cyclic adenosine 3',5'-monophosphate levels. In addition, the activation of ovarian taste receptors induced apoptosis, possibly through NO and mitogen-activated protein kinase signaling. As a result, the activation of ovarian taste receptors reduced the protein expression of steroidogenesis-related factors, causing the inhibition of ovarian progesterone production. In summary, our data suggest that the activation of ovarian taste receptors inhibits progesterone production in pseudopregnant rats, potentially via NO/cGMP and apoptotic signaling.
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Affiliation(s)
- Jingle Jiang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Siyi Liu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Lina Qi
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Quanwei Wei
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Fangxiong Shi
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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7
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Ahmad R, Dalziel JE. G Protein-Coupled Receptors in Taste Physiology and Pharmacology. Front Pharmacol 2020; 11:587664. [PMID: 33390961 PMCID: PMC7774309 DOI: 10.3389/fphar.2020.587664] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022] Open
Abstract
Heterotrimeric G protein-coupled receptors (GPCRs) comprise the largest receptor family in mammals and are responsible for the regulation of most physiological functions. Besides mediating the sensory modalities of olfaction and vision, GPCRs also transduce signals for three basic taste qualities of sweet, umami (savory taste), and bitter, as well as the flavor sensation kokumi. Taste GPCRs reside in specialised taste receptor cells (TRCs) within taste buds. Type I taste GPCRs (TAS1R) form heterodimeric complexes that function as sweet (TAS1R2/TAS1R3) or umami (TAS1R1/TAS1R3) taste receptors, whereas Type II are monomeric bitter taste receptors or kokumi/calcium-sensing receptors. Sweet, umami and kokumi receptors share structural similarities in containing multiple agonist binding sites with pronounced selectivity while most bitter receptors contain a single binding site that is broadly tuned to a diverse array of bitter ligands in a non-selective manner. Tastant binding to the receptor activates downstream secondary messenger pathways leading to depolarization and increased intracellular calcium in TRCs, that in turn innervate the gustatory cortex in the brain. Despite recent advances in our understanding of the relationship between agonist binding and the conformational changes required for receptor activation, several major challenges and questions remain in taste GPCR biology that are discussed in the present review. In recent years, intensive integrative approaches combining heterologous expression, mutagenesis and homology modeling have together provided insight regarding agonist binding site locations and molecular mechanisms of orthosteric and allosteric modulation. In addition, studies based on transgenic mice, utilizing either global or conditional knock out strategies have provided insights to taste receptor signal transduction mechanisms and their roles in physiology. However, the need for more functional studies in a physiological context is apparent and would be enhanced by a crystallized structure of taste receptors for a more complete picture of their pharmacological mechanisms.
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Affiliation(s)
- Raise Ahmad
- Food Nutrition and Health Team, Food and Bio-based Products Group, AgResearch, Palmerston North, New Zealand
| | - Julie E Dalziel
- Food Nutrition and Health Team, Food and Bio-based Products Group, AgResearch, Palmerston North, New Zealand
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8
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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: 17] [Impact Index Per Article: 4.3] [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.
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9
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Hunter SR, Reister EJ, Cheon E, Mattes RD. Low Calorie Sweeteners Differ in Their Physiological Effects in Humans. Nutrients 2019; 11:E2717. [PMID: 31717525 PMCID: PMC6893706 DOI: 10.3390/nu11112717] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/04/2019] [Accepted: 11/06/2019] [Indexed: 12/13/2022] Open
Abstract
Low calorie sweeteners (LCS) are prevalent in the food supply for their primary functional property of providing sweetness with little or no energy. Though tested for safety individually, there has been extremely limited work on the efficacy of each LCS. It is commonly assumed all LCS act similarly in their behavioral and physiological effects. However, each LCS has its own chemical structure that influences its metabolism, making each LCS unique in its potential effects on body weight, energy intake, and appetite. LCS may have different behavioral and physiological effects mediated at the sweet taste receptor, in brain activation, with gut hormones, at the microbiota and on appetitive responses. Further elucidation of the unique effects of the different commercially available LCS may hold important implications for recommendations about their use for different health outcomes.
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Affiliation(s)
| | | | | | - Richard D. Mattes
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA; (S.R.H.); (E.J.R.); (E.C.)
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10
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Purification and sweetness properties of egg white lysozymes from Indonesian local poultry of ayam kampung and Cihateup duck. JOURNAL OF FOOD MEASUREMENT AND CHARACTERIZATION 2019. [DOI: 10.1007/s11694-019-00299-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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11
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Wulandari Z, Fardiaz D, Thenawijaya M, Dewi Yuliana N, Budiman C. ISOLASI LISOZIM ALBUMIN TELUR AYAM RAS DENGAN METODE KROMATOGRAFI PENUKAR ION. JURNAL TEKNOLOGI DAN INDUSTRI PANGAN 2018. [DOI: 10.6066/jtip.2018.29.2.155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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12
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Masuda T, Okubo K, Murata K, Mikami B, Sugahara M, Suzuki M, Temussi PA, Tani F. Subatomic structure of hyper-sweet thaumatin D21N mutant reveals the importance of flexible conformations for enhanced sweetness. Biochimie 2018; 157:57-63. [PMID: 30389513 DOI: 10.1016/j.biochi.2018.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 10/26/2018] [Indexed: 01/26/2023]
Abstract
One of the sweetest proteins found in tropical fruits (with a threshold of 50 nM), thaumatin, is also used commercially as a sweetener. Our previous study successfully produced the sweetest thaumatin mutant (D21N), designated hyper-sweet thaumatin, which decreases the sweetness threshold to 31 nM. To investigate why the D21N mutant is sweeter than wild-type thaumatin, we compared the structure of the D21N mutant solved at a subatomic resolution of 0.93 Å with that of wild-type thaumatin determined at 0.90 Å. Although the overall structure of the D21N mutant resembles that of wild-type thaumatin, our subatomic resolution analysis successfully assigned and discriminated the detailed atomic positions of side-chains at position 21. The relative B-factor value of the side-chain at position 21 in the D21N mutant was higher than that of wild-type thaumatin, hinting at a greater flexibility of side-chain at 21 in the hyper-sweet D21N mutant. Furthermore, alternative conformations of Lys19, which is hydrogen-bonded to Asp21 in wild-type, were found only in the D21N mutant. Subatomic resolution analysis revealed that flexible conformations at the sites adjacent to positions 19 and 21 play a crucial role in enhancing sweet potency and may serve to enhance the complementarity of electrostatic potentials for interaction with the sweet taste receptor.
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Affiliation(s)
- Tetsuya Masuda
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
| | - Kyohei Okubo
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Kazuki Murata
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Bunzo Mikami
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Michihiro Sugahara
- RIKEN SPring-8 Center, Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Mamoru Suzuki
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Piero Andrea Temussi
- Department of Basic and Clinical Neurosciences, King's College London, London, SE59RX, UK; Dipartimento di Chimica, Universita' di Napoli Federico II, Napoli, I-80126, Italy
| | - Fumito Tani
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
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Healey RD, Wojciechowski JP, Monserrat-Martinez A, Tan SL, Marquis CP, Sierecki E, Gambin Y, Finch AM, Thordarson P. Design, Synthesis, and Evaluation of N- and C-Terminal Protein Bioconjugates as G Protein-Coupled Receptor Agonists. Bioconjug Chem 2018; 29:403-409. [PMID: 29328675 DOI: 10.1021/acs.bioconjchem.7b00716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A G protein-coupled receptor (GPCR) agonist protein, thaumatin, was site-specifically conjugated at the N- or C-terminus with a fluorophore for visualization of GPCR:agonist interactions. The N-terminus was specifically conjugated using a synthetic 2-pyridinecarboxyaldehyde reagent. The interaction profiles observed for N- and C-terminal conjugates were varied; N-terminal conjugates interacted very weakly with the GPCR of interest, whereas C-terminal conjugates bound to the receptor. These chemical biology tools allow interactions of therapeutic proteins:GPCR to be monitored and visualized. The methodology used for site-specific bioconjugation represents an advance in application of 2-pyridinecarboxyaldehydes for N-terminal specific bioconjugations.
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Affiliation(s)
- Robert D Healey
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, §School of Medical Sciences, ‡EMBL Australia Node of Single Molecule Science, and ⊥School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, 2052 New South Wales, Australia
| | - Jonathan P Wojciechowski
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, §School of Medical Sciences, ‡EMBL Australia Node of Single Molecule Science, and ⊥School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, 2052 New South Wales, Australia
| | - Ana Monserrat-Martinez
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, §School of Medical Sciences, ‡EMBL Australia Node of Single Molecule Science, and ⊥School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, 2052 New South Wales, Australia
| | - Susan L Tan
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, §School of Medical Sciences, ‡EMBL Australia Node of Single Molecule Science, and ⊥School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, 2052 New South Wales, Australia
| | - Christopher P Marquis
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, §School of Medical Sciences, ‡EMBL Australia Node of Single Molecule Science, and ⊥School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, 2052 New South Wales, Australia
| | - Emma Sierecki
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, §School of Medical Sciences, ‡EMBL Australia Node of Single Molecule Science, and ⊥School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, 2052 New South Wales, Australia
| | - Yann Gambin
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, §School of Medical Sciences, ‡EMBL Australia Node of Single Molecule Science, and ⊥School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, 2052 New South Wales, Australia
| | - Angela M Finch
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, §School of Medical Sciences, ‡EMBL Australia Node of Single Molecule Science, and ⊥School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, 2052 New South Wales, Australia
| | - Pall Thordarson
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, §School of Medical Sciences, ‡EMBL Australia Node of Single Molecule Science, and ⊥School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, 2052 New South Wales, Australia
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14
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Masuda T, Kigo S, Mitsumoto M, Ohta K, Suzuki M, Mikami B, Kitabatake N, Tani F. Positive Charges on the Surface of Thaumatin Are Crucial for the Multi-Point Interaction with the Sweet Receptor. Front Mol Biosci 2018; 5:10. [PMID: 29487853 PMCID: PMC5816810 DOI: 10.3389/fmolb.2018.00010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 01/24/2018] [Indexed: 11/21/2022] Open
Abstract
Thaumatin, an intensely sweet-tasting protein, elicits sweet taste with a threshold of only 50 nM. Previous studies from our laboratory suggested that the complex model between the T1R2-T1R3 sweet receptor and thaumatin depends critically on the complementarity of electrostatic potentials. In order to further validate this model, we focused on three lysine residues (Lys78, Lys106, and Lys137), which were expected to be part of the interaction sites. Three thaumatin mutants (K78A, K106A, and K137A) were prepared and their threshold values of sweetness were examined. The results showed that the sweetness of K106A was reduced by about three times and those of K78A and K137A were reduced by about five times when compared to wild-type thaumatin. The three-dimensional structures of these mutants were also determined by X-ray crystallographic analyses at atomic resolutions. The overall structures of mutant proteins were similar to that of wild-type but the electrostatic potentials around the mutated sites became more negative. Since the three lysine residues are located in 20-40 Å apart each other on the surface of thaumatin molecule, these results suggest the positive charges on the surface of thaumatin play a crucial role in the interaction with the sweet receptor, and are consistent with a large surface is required for interaction with the sweet receptor, as proposed by the multipoint interaction model named wedge model.
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Affiliation(s)
- Tetsuya Masuda
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Japan
| | - Satomi Kigo
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Japan
| | - Mayuko Mitsumoto
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Japan
| | - Keisuke Ohta
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Japan
| | - Mamoru Suzuki
- Laboratory of Supramolecular Crystallography, Research Center for State-of-the-Art Functional Protein Analysis, Institute for Protein Research, Osaka University, Suita, Japan
| | - Bunzo Mikami
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Uji, Japan
| | - Naofumi Kitabatake
- Department of Foods and Human Nutrition, Notre Dame Seishin University, Okayama, Japan
| | - Fumito Tani
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Japan
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Kikut-Ligaj D, Trzcielińska-Lorych J. How taste works: cells, receptors and gustatory perception. Cell Mol Biol Lett 2016; 20:699-716. [PMID: 26447485 DOI: 10.1515/cmble-2015-0042] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 09/15/2015] [Indexed: 11/15/2022] Open
Abstract
The sensitivity of taste in mammals varies due to quantitative and qualitative differences in the structure of the taste perception organs. Gustatory perception is made possible by the peripheral chemosensory organs, i.e., the taste buds, which are distributed in the epithelium of the taste papillae of the palate, tongue, epiglottis, throat and larynx. Each taste bud consists of a community of ~100 cells that process and integrate taste information with metabolic needs. Mammalian taste buds are contained in circumvallate, fungiform and foliate papillae and react to sweet, salty, sour, bitter and umami stimuli. The sensitivity of the taste buds for individual taste stimuli varies extensively and depends on the type of papillae and the part of the oral cavity in which they are located. There are at least three different cell types found in mammalian taste buds: type I cells, receptor (type II) cells and presynaptic (type III) cells. This review focuses on the biophysiological mechanisms of action of the various taste stimuli in humans. Currently, the best-characterized proteins are the receptors (GPCR). In addition, the activation of bitter, sweet and umami tastes are relatively well known, but the activation of salty and sour tastes has yet to be clearly explained.
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A Hypersweet Protein: Removal of The Specific Negative Charge at Asp21 Enhances Thaumatin Sweetness. Sci Rep 2016; 6:20255. [PMID: 26837600 PMCID: PMC4738316 DOI: 10.1038/srep20255] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/31/2015] [Indexed: 11/26/2022] Open
Abstract
Thaumatin is an intensely sweet-tasting protein that elicits sweet taste at a concentration of 50 nM, a value 100,000 times larger than that of sucrose on a molar basis. Here we attempted to produce a protein with enhanced sweetness by removing negative charges on the interacting side of thaumatin with the taste receptor. We obtained a D21N mutant which, with a threshold value 31 nM is much sweeter than wild type thaumatin and, together with the Y65R mutant of single chain monellin, one of the two sweetest proteins known so far. The complex model between the T1R2-T1R3 sweet receptor and thaumatin, derived from tethered docking in the framework of the wedge model, confirmed that each of the positively charged residues critical for sweetness is close to a receptor residue of opposite charge to yield optimal electrostatic interaction. Furthermore, the distance between D21 and its possible counterpart D433 (located on the T1R2 protomer of the receptor) is safely large to avoid electrostatic repulsion but, at the same time, amenable to a closer approach if D21 is mutated into the corresponding asparagine. These findings clearly confirm the importance of electrostatic potentials in the interaction of thaumatin with the sweet receptor.
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Matano M, Nakajima K, Kashiwagi Y, Udaka S, Maehashi K. Sweetness characterization of recombinant human lysozyme. Comp Biochem Physiol B Biochem Mol Biol 2015; 188:8-14. [DOI: 10.1016/j.cbpb.2015.05.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 05/18/2015] [Accepted: 05/21/2015] [Indexed: 11/26/2022]
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18
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Healey RD, Prasad S, Rajendram V, Thordarson P. Unravelling the interaction between α-cyclodextrin with the thaumatin protein and a peptide mimic. Supramol Chem 2014. [DOI: 10.1080/10610278.2014.956745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Robert D. Healey
- School of Chemistry and Australian Centre for Nanomedicine, The University of New South Wales, Sydney, NSW2052, Australia
| | - Shiva Prasad
- Neptune Bio-Innovations Pty. Ltd., 140 Wicks Road, North Ryde, NSW2113, Australia
| | - Vijaya Rajendram
- Neptune Bio-Innovations Pty. Ltd., 140 Wicks Road, North Ryde, NSW2113, Australia
| | - Pall Thordarson
- School of Chemistry and Australian Centre for Nanomedicine, The University of New South Wales, Sydney, NSW2052, Australia
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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] [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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Hellfritsch C, Brockhoff A, Stähler F, Meyerhof W, Hofmann T. Human psychometric and taste receptor responses to steviol glycosides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:6782-6793. [PMID: 22616809 DOI: 10.1021/jf301297n] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Steviol glycosides, the sweet principle of Stevia Rebaudiana (Bertoni) Bertoni, have recently been approved as a food additive in the EU. The herbal non-nutritive high-potency sweeteners perfectly meet the rising consumer demand for natural food ingredients in Europe. We have characterized the organoleptic properties of the most common steviol glycosides by an experimental approach combining human sensory studies and cell-based functional taste receptor expression assays. On the basis of their potency to elicit sweet and bitter taste sensations, we identified glycone chain length, pyranose substitution, and the C16 double bond as the structural features giving distinction to the gustatory profile of steviol glycosides. A comprehensive screening of 25 human bitter taste receptors revealed that two receptors, hTAS2R4 and hTAS2R14, mediate the bitter off-taste of steviol glycosides. For some test substances, e.g., stevioside, we observed a decline in sweet intensity at supra-maximum concentrations. This effect did not arise from allosteric modulation of the hTAS1R2/R3 sweet taste receptor but might be explained by intramolecular cross-modal suppression between the sweet and bitter taste component of steviol glycosides. These results might contribute to the production of preferentially sweet and least bitter tasting Stevia extracts by an optimization of breeding and postharvest downstream processing.
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Affiliation(s)
- Caroline Hellfritsch
- Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München , Lise-Meitner-Strasse 34, D-85354 Freising-Weihenstephan, Germany
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21
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Gustatory and extragustatory functions of mammalian taste receptors. Physiol Behav 2011; 105:4-13. [DOI: 10.1016/j.physbeh.2011.02.010] [Citation(s) in RCA: 172] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/01/2011] [Accepted: 02/07/2011] [Indexed: 01/05/2023]
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22
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Introduction of a negative charge at Arg82 in thaumatin abolished responses to human T1R2–T1R3 sweet receptors. Biochem Biophys Res Commun 2011; 413:41-5. [DOI: 10.1016/j.bbrc.2011.08.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 08/08/2011] [Indexed: 11/15/2022]
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23
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Ohta K, Masuda T, Tani F, Kitabatake N. The cysteine-rich domain of human T1R3 is necessary for the interaction between human T1R2–T1R3 sweet receptors and a sweet-tasting protein, thaumatin. Biochem Biophys Res Commun 2011; 406:435-8. [DOI: 10.1016/j.bbrc.2011.02.063] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Accepted: 02/11/2011] [Indexed: 12/01/2022]
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24
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Behrens M, Meyerhof W, Hellfritsch C, Hofmann T. Moleküle und biologische Mechanismen des Süß- und Umamigeschmacks. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201002094] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Behrens M, Meyerhof W, Hellfritsch C, Hofmann T. Sweet and Umami Taste: Natural Products, Their Chemosensory Targets, and Beyond. Angew Chem Int Ed Engl 2011; 50:2220-42. [DOI: 10.1002/anie.201002094] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Indexed: 11/11/2022]
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