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Pinillos P, Camiruaga A, Torres-Hernández F, Çarçabal P, Usabiaga I, Fernández JA, Martínez R. Aspartame and Its Microhydrated Aggregates Revealed by Laser Spectroscopy: Water-Sweetener Interactions in the Gas Phase. J Phys Chem A 2024. [PMID: 39091218 DOI: 10.1021/acs.jpca.4c04315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
The popular sweetener, aspartame, is an agonist of the tongue's sweet taste receptor. How water molecules affect its conformation or which aspartame atoms are more prone to interact with solvent are helpful questions to understand its activity in different environments. Here, the combination of IR-UV spectroscopic techniques with computational simulations has been successfully applied to characterize aspartame·water0-2 clusters, showing that the addition of water molecules simplifies the conformational panorama of aspartame, favoring the formation of folded structures by interaction with the polar part of the molecule.
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Affiliation(s)
- Paul Pinillos
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), B° Sarriena S/N, Leioa 48940, Spain
| | - Ander Camiruaga
- Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris Saclay, CNRS, Orsay 91405, France
| | - Fernando Torres-Hernández
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), B° Sarriena S/N, Leioa 48940, Spain
| | - Pierre Çarçabal
- Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris Saclay, CNRS, Orsay 91405, France
| | - Imanol Usabiaga
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), B° Sarriena S/N, Leioa 48940, Spain
| | - José A Fernández
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), B° Sarriena S/N, Leioa 48940, Spain
| | - Rodrigo Martínez
- Department of Chemistry, Faculty of Science and Technology, University of La Rioja, Madre de Dios 53, Logroño 26006, Spain
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2
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Wang Y, Chang S, Lu S, Tong M, Kong F, Liu B. The sweet taste receptors in Lemuriformes respond to aspartame, a non-nutritive sweetener and critical residues mediating their taste. Biochimie 2024:S0300-9084(24)00164-0. [PMID: 38996999 DOI: 10.1016/j.biochi.2024.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 07/02/2024] [Accepted: 07/09/2024] [Indexed: 07/14/2024]
Abstract
Aspartame is a high potency artificial sweetener which is popularly used in foods and beverages. The species-dependent sweet taste toward aspartame has not been completely understood. In a recent publication, we reported that the prosimians Lemuriformes species, which are proposed as aspartame nontasters, could taste aspartame based on the sequence and structure analysis. In this study, by mutagenesis, cell-based functional analysis and molecular simulations, we reveal that Lemuriformes species can respond to aspartame at the cell-based receptor activity level. Furthermore, it is proved that the conserved critical residues D142 and S40 mediate the species-dependent sweet taste toward aspartame. This research provides a deeper insight on the species taste, structure-activity relationship and evolution for eliciting the sweetness of this important synthetic sweetener.
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Affiliation(s)
- Yuqing Wang
- Department of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, 250353, China
| | - Shiyu Chang
- Tobacco Research Institute, Laboratory of Tobacco and Aromatic Plants Quality and Safety Risk Assessment, Ministry of Agriculture and Rural Affairs, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
| | - Shangyang Lu
- Department of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, 250353, China
| | - Mingqiong Tong
- School of Medicine and Nursing, Dezhou University, Dezhou, Shandong, 253023, China
| | - Fanyu Kong
- Tobacco Research Institute, Laboratory of Tobacco and Aromatic Plants Quality and Safety Risk Assessment, Ministry of Agriculture and Rural Affairs, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
| | - Bo Liu
- Department of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, 250353, China.
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3
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Yoshida R, Ninomiya Y. Mechanisms and Functions of Sweet Reception in Oral and Extraoral Organs. Int J Mol Sci 2024; 25:7398. [PMID: 39000505 PMCID: PMC11242429 DOI: 10.3390/ijms25137398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/27/2024] [Accepted: 07/03/2024] [Indexed: 07/16/2024] Open
Abstract
The oral detection of sugars relies on two types of receptor systems. The first is the G-protein-coupled receptor TAS1R2/TAS1R3. When activated, this receptor triggers a downstream signaling cascade involving gustducin, phospholipase Cβ2 (PLCβ2), and transient receptor potential channel M5 (TRPM5). The second type of receptor is the glucose transporter. When glucose enters the cell via this transporter, it is metabolized to produce ATP. This ATP inhibits the opening of KATP channels, leading to cell depolarization. Beside these receptor systems, sweet-sensitive taste cells have mechanisms to regulate their sensitivity to sweet substances based on internal and external states of the body. Sweet taste receptors are not limited to the oral cavity; they are also present in extraoral organs such as the gastrointestinal tract, pancreas, and brain. These extraoral sweet receptors are involved in various functions, including glucose absorption, insulin release, sugar preference, and food intake, contributing to the maintenance of energy homeostasis. Additionally, sweet receptors may have unique roles in certain organs like the trachea and bone. This review summarizes past and recent studies on sweet receptor systems, exploring the molecular mechanisms and physiological functions of sweet (sugar) detection in both oral and extraoral organs.
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Affiliation(s)
- Ryusuke Yoshida
- Department of Oral Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8525, Japan
- Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan
| | - Yuzo Ninomiya
- Department of Oral Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8525, Japan
- Graduate School of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA
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4
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Serrano J, Boyd J, Brown IS, Mason C, Smith KR, Karolyi K, Maurya SK, Meshram NN, Serna V, Link GM, Gardell SJ, Kyriazis GA. The TAS1R2 G-protein-coupled receptor is an ambient glucose sensor in skeletal muscle that regulates NAD homeostasis and mitochondrial capacity. Nat Commun 2024; 15:4915. [PMID: 38851747 PMCID: PMC11162498 DOI: 10.1038/s41467-024-49100-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 05/21/2024] [Indexed: 06/10/2024] Open
Abstract
The bioavailability of nicotinamide adenine dinucleotide (NAD) is vital for skeletal muscle health, yet the mechanisms or signals regulating NAD homeostasis remain unclear. Here, we uncover a pathway connecting peripheral glucose sensing to the modulation of muscle NAD through TAS1R2, the sugar-sensing G protein-coupled receptor (GPCR) initially identified in taste perception. Muscle TAS1R2 receptor stimulation by glucose and other agonists induces ERK1/2-dependent phosphorylation and activation of poly(ADP-ribose) polymerase1 (PARP1), a major NAD consumer in skeletal muscle. Consequently, muscle-specific deletion of TAS1R2 (mKO) in male mice suppresses PARP1 activity, elevating NAD levels and enhancing mitochondrial capacity and running endurance. Plasma glucose levels negatively correlate with muscle NAD, and TAS1R2 receptor deficiency enhances NAD responses across the glycemic range, implicating TAS1R2 as a peripheral energy surveyor. These findings underscore the role of GPCR signaling in NAD regulation and propose TAS1R2 as a potential therapeutic target for maintaining muscle health.
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Affiliation(s)
- Joan Serrano
- Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA
| | - Jordan Boyd
- Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA
| | - Ian S Brown
- Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA
| | - Carter Mason
- Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA
| | - Kathleen R Smith
- Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA
| | - Katalin Karolyi
- Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA
| | - Santosh K Maurya
- Physiology and Cell Biology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA
| | - Nishita N Meshram
- Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA
| | - Vanida Serna
- Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA
| | - Grace M Link
- Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA
| | - Stephen J Gardell
- Translational Research Institute, Advent Health, Orlando, 32804, USA
| | - George A Kyriazis
- Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University; Columbus, Columbus, 43210, USA.
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5
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Smith L, Moran AW, Al-Rammahi M, Daly K, Shirazi-Beechey SP. Determination of sweetener specificity of horse gut-expressed sweet taste receptor T1R2-T1R3 and its significance for energy provision and hydration. Front Vet Sci 2024; 11:1325135. [PMID: 38410741 PMCID: PMC10894948 DOI: 10.3389/fvets.2024.1325135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/23/2024] [Indexed: 02/28/2024] Open
Abstract
Studies carried out in several species have demonstrated that detection of low-calorie sweeteners in the lumen of the intestine, by the sweet receptor, T1R2-T1R3, initiates a signaling pathway leading to enhanced expression and activity of intestinal Na+/glucose cotransporter 1, SGLT1. This results in an increased gut capacity to absorb glucose, sodium chloride and water, the basis for oral rehydration therapy. Horses express T1R2, T1R3 and downstream signaling elements in the intestinal tissue. As such, the potential of sweetener-stimulation of T1R2-T1R3 leading to upregulation of SGLT1 allows the provision of more glucose (energy) and hydration for horses. This is especially important when the need for glucose increases during strenuous exercise, pregnancy, and lactation. There are significant differences among species in the ability to detect sweeteners. Amino acid substitutions and pseudogenization of taste receptor genes underlie these variations. Nothing is known about the sweetener specificity of horse T1R2-T1R3. Using heterologous expression methodology, we demonstrate that sweeteners sucralose, stevia and neohesperidin dihydrochalcone (NHDC) activate horse T1R2-T1R3, but cyclamate does not. Determination of sweetener specificity of equine sweet receptor is crucial for developing suitable dietary additives to optimize glucose absorption, hydration and avoiding the intestinal disease brought about by microbial fermentation of unabsorbed carbohydrate reaching the large intestine.
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Affiliation(s)
- Liberty Smith
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Andrew W. Moran
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Miran Al-Rammahi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
- Department of Physiology, Biochemistry and Pharmacology, College of Veterinary Medicine, University of Al-Qadisiyah, Al-Diwaniyah, Iraq
| | - Kristian Daly
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Soraya P. Shirazi-Beechey
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
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6
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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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7
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Yang J, Myers J, Slaughter MM. Saccharin and aspartame excite rat retinal neurons. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1273575. [PMID: 38983093 PMCID: PMC11182259 DOI: 10.3389/fopht.2023.1273575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 09/19/2023] [Indexed: 07/11/2024]
Abstract
Retinal sensitivity to a variety of artificial sweeteners was tested by monitoring changes in internal free calcium in isolated retinal neurons using Fluo3. Several ligands, including aspartame and saccharin elevated internal free calcium. The effects of these ligands were mediated by both ligand-gated membrane channels and G-protein coupled receptors. We explored the receptors responsible for this phenomenon. Surprisingly, mRNA for subunits of the sweet taste receptor dimer (T1R2 and T1R3) were found in retina. Interestingly, knockdown of T1R2 reduced the response to saccharin but not aspartame. But TRPV1 channel antagonists suppressed the responses to aspartame. The results indicate that artificial sweeteners can increase internal free calcium in the retinal neurons through multiple pathways. Furthermore, aspartame reduced the b-wave, but not the a-wave, of the electroretinogram, indicating disruption of communication between photoreceptors and second order neurons.
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Affiliation(s)
| | | | - Malcolm M. Slaughter
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, NY, United States
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Rayo-Morales R, Segura-Carretero A, Borras-Linares I, Garcia-Burgos D. Suppression of sweet taste-related responses by plant-derived bioactive compounds and eating. Part I: A systematic review in humans. Heliyon 2023; 9:e19733. [PMID: 37817998 PMCID: PMC10560784 DOI: 10.1016/j.heliyon.2023.e19733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 10/12/2023] Open
Abstract
The taste of food plays a crucial role in determining what and how much we eat. Thus, interventions that temporarily block sweet taste receptors offer a promising approach to addressing unhealthy behaviours associated with sugary foods. However, the relationship between reduced sweet taste response and food consumption remains unclear, with contradictory findings. Certain studies suggest that a diminished perception of sweetness leads to a sense of fullness and results in reduced food intake, while others suggest the opposite effect. To shed some light, our systematic review looked into the relationship between diminished sweet taste response and food consumption by examining the effects of bioactive compounds that experimentally inhibit sweetness in healthy individuals. This review was registered in the International Prospective Register of Systematic Reviews and conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the Scottish Intercollegiate Guidelines Network, and covered original papers included in Web of Science, PubMed, Scopus, Food Science Source and Food Science and technology abstracts. We identified 33 peer-reviewed English-language studies that fit the topic and met the inclusion criteria. The current literature predominantly focuses on the immediate impact of oral gymnemic acids, failing to provide preliminary evidence in support of the specific threshold hypothesis, above which food consumption decreases and below which the opposite effect occurs. Additionally, there was inconsistency in the findings regarding the short-term desire to eat following sweetness inhibition. Considering the downstream effects on energy intake and their clinical applications, further research is needed to clarify both the acute within-session effects (i.e., not wanting any more now) and the longer-term effects (i.e., deciding not to start eating) linked to oral sweet-taste-suppressing compounds.
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Affiliation(s)
- Raquel Rayo-Morales
- Department of Analytical Chemistry, Faculty of Science, University of Granada, 18071 Granada, Spain
- Department of Psychobiology, Institute of Neurosciences, Centre for Biomedical Research, University of Granada, 18010, Granada, Spain
| | - Antonio Segura-Carretero
- Department of Analytical Chemistry, Faculty of Science, University of Granada, 18071 Granada, Spain
| | - Isabel Borras-Linares
- Department of Analytical Chemistry, Faculty of Science, University of Granada, 18071 Granada, Spain
| | - David Garcia-Burgos
- Department of Psychobiology, Institute of Neurosciences, Centre for Biomedical Research, University of Granada, 18010, Granada, Spain
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Kouakou YI, Lee RJ. Interkingdom Detection of Bacterial Quorum-Sensing Molecules by Mammalian Taste Receptors. Microorganisms 2023; 11:1295. [PMID: 37317269 DOI: 10.3390/microorganisms11051295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/11/2023] [Accepted: 05/13/2023] [Indexed: 06/16/2023] Open
Abstract
Bitter and sweet taste G protein-coupled receptors (known as T2Rs and T1Rs, respectively) were originally identified in type II taste cells on the tongue, where they signal perception of bitter and sweet tastes, respectively. Over the past ~15 years, taste receptors have been identified in cells all over the body, demonstrating a more general chemosensory role beyond taste. Bitter and sweet taste receptors regulate gut epithelial function, pancreatic β cell secretion, thyroid hormone secretion, adipocyte function, and many other processes. Emerging data from a variety of tissues suggest that taste receptors are also used by mammalian cells to "eavesdrop" on bacterial communications. These receptors are activated by several quorum-sensing molecules, including acyl-homoserine lactones and quinolones from Gram-negative bacteria such as Pseudomonas aeruginosa, competence stimulating peptides from Streptococcus mutans, and D-amino acids from Staphylococcus aureus. Taste receptors are an arm of immune surveillance similar to Toll-like receptors and other pattern recognition receptors. Because they are activated by quorum-sensing molecules, taste receptors report information about microbial population density based on the chemical composition of the extracellular environment. This review summarizes current knowledge of bacterial activation of taste receptors and identifies important questions remaining in this field.
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Affiliation(s)
- Yobouet Ines Kouakou
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert J Lee
- Department of Otorhinolaryngology and Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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10
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Chometton S, Tsan L, Hayes AMR, Kanoski SE, Schier LA. Early-life influences of low-calorie sweetener consumption on sugar taste. Physiol Behav 2023; 264:114133. [PMID: 36801464 PMCID: PMC11062773 DOI: 10.1016/j.physbeh.2023.114133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/21/2023]
Abstract
Children and adolescents are the highest consumers of added sugars, particularly from sugar-sweetened beverages (SSB). Regular consumption of SSB early in life induces a variety of negative consequences on health that can last into adulthood. Low-calorie sweeteners (LCS) are increasingly used as an alternative to added sugars because they provide a sweet sensation without adding calories to the diet. However, the long-term effects of early-life consumption of LCS are not well understood. Considering LCS engage at least one of the same taste receptors as sugars and potentially modulate cellular mechanisms of glucose transport and metabolism, it is especially important to understand how early-life LCS consumption impacts intake of and regulatory responses to caloric sugars. In our recent study, we found that habitual intake of LCS during the juvenile-adolescence period significantly changed how rats responded to sugar later in life. Here, we review evidence that LCS and sugars are sensed via common and distinct gustatory pathways, and then discuss the implications this has for shaping sugar-associated appetitive, consummatory, and physiological responses. Ultimately, the review highlights the diverse gaps in knowledge that will be necessary to fill to understand the consequences of regular LCS consumption during important phases of development.
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Affiliation(s)
- Sandrine Chometton
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, USA
| | - Linda Tsan
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, USA
| | - Anna M R Hayes
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, USA
| | - Scott E Kanoski
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, USA
| | - Lindsey A Schier
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, USA.
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Evangelista-Falcón W, Denhez C, Baena-Moncada A, Ponce-Vargas M. Revisiting the Sweet Taste Receptor T1R2-T1R3 through Molecular Dynamics Simulations Coupled with a Noncovalent Interactions Analysis. J Phys Chem B 2023; 127:1110-1119. [PMID: 36705604 DOI: 10.1021/acs.jpcb.2c07180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
It is nowadays widely accepted that sweet taste perception is elicited by the activation of the heterodimeric complex T1R2-T1R3, customarily known as sweet taste receptor (STR). However, the interplay between STR and sweeteners has not yet been fully clarified. Here through a methodology coupling molecular dynamics and the independent gradient model (igm) approach we determine the main interacting signatures of the closed (active) conformation of the T1R2 Venus flytrap domain (VFD) toward aspartame. The igm methodology provides a rapid and reliable quantification of noncovalent interactions through a score (Δginter) based on the attenuation of the electronic density gradient when two molecular fragments approach each other. Herein, this approach is coupled to a 100 ns molecular dynamics simulation (MD-igm) to explore the ligand-cavity contacts on a per-residue basis as well as a series of key inter-residue interactions that stabilize the closed form of VFD. We also apply an atomic decomposition scheme of noncovalent interactions to quantify the contribution of the ligand segments to the noncovalent interplay. Finally, a series of structural modification on aspartame are conducted in order to obtain guidelines for the rational design of novel sweeteners. Given that innovative methodologies to reliably quantify the extent of ligand-protein coupling are strongly demanded, this approach combining a noncovalent analysis and MD simulations represents a valuable contribution, that can be easily applied to other relevant biomolecular systems.
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Affiliation(s)
- Wilfredo Evangelista-Falcón
- Laboratory of Biomolecules, Faculty of Health Sciences, Universidad Peruana de Ciencias Aplicadas, Lima15023, Perú
| | - Clément Denhez
- Institut de Chimie Moléculaire de Reims UMR CNRS 7312, Université de Reims Champagne-Ardenne, Moulin de la Housse 51687, ReimsCedex 02 BP39, France
| | - Angélica Baena-Moncada
- Laboratorio de Investigación de Electroquímica Aplicada, Facultad de Ciencias de la Universidad Nacional de Ingeniería, Av. Túpac Amaru 210, Rímac, Lima31-139, Perú
| | - Miguel Ponce-Vargas
- Institut de Chimie Moléculaire de Reims UMR CNRS 7312, Université de Reims Champagne-Ardenne, Moulin de la Housse 51687, ReimsCedex 02 BP39, France
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12
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Wang C, Liu Y, Cui M, Liu B. Systematic analysis reveals novel insight into the molecular determinants of function, diversity and evolution of sweet taste receptors T1R2/T1R3 in primates. Front Mol Biosci 2023; 10:1037966. [PMID: 36762208 PMCID: PMC9905694 DOI: 10.3389/fmolb.2023.1037966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 01/13/2023] [Indexed: 01/26/2023] Open
Abstract
Sweet taste is a primary sensation for the preference and adaption of primates to diet, which is crucial for their survival and fitness. It is clear now that the sweet perception is mediated by a G protein-coupled receptor (GPCR)-sweet taste receptor T1R2/T1R3, and many behavioral or physiological experiments have described the diverse sweet taste sensitivities in primates. However, the structure-function relationship of T1R2s/T1R3s in primates, especially the molecular basis for their species-dependent sweet taste, has not been well understood until now. In this study, we performed a comprehensive sequence, structural and functional analysis of sweet taste receptors in primates to elucidate the molecular determinants mediating their species-dependent sweet taste recognition. Our results reveal distinct taxonomic distribution and significant characteristics (interaction, coevolution and epistasis) of specific key function-related residues, which could partly account for the previously reported behavioral results of taste perception in primates. Moreover, the prosimians Lemuriformes species, which were reported to have no sensitivity to aspartame, could be proposed to be aspartame tasters based on the present analysis. Collectively, our study provides new insights and promotes a better understanding for the diversity, function and evolution of sweet taste receptors in primates.
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Affiliation(s)
- Congrui Wang
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Yi Liu
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, United States,*Correspondence: Meng Cui, ; Bo Liu,
| | - Bo Liu
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China,*Correspondence: Meng Cui, ; Bo Liu,
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13
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Chontzopoulou E, Papaemmanouil CD, Chatziathanasiadou MV, Kolokouris D, Kiriakidi S, Konstantinidi A, Gerogianni I, Tselios T, Kostakis IK, Chrysina ED, Hadjipavlou-Litina D, Tzeli D, Tzakos AG, Mavromoustakos T. Molecular investigation of artificial and natural sweeteners as potential anti-inflammatory agents. J Biomol Struct Dyn 2022; 40:12608-12620. [PMID: 34499023 DOI: 10.1080/07391102.2021.1973565] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Repurposing existing drugs, as well as natural and artificial sweeteners for novel therapeutic indications could speed up the drug discovery process since numerous associated risks and costs for drug development can be surpassed. In this study, natural and artificial sweeteners have been evaluated by in silico and experimental studies for their potency to inhibit lipoxygenase enzyme, an enzyme participating in the inflammation pathway. A variety of different methods pinpointed that aspartame inhibits the lipoxygenase isoform 1 (LOX-1). In particular, "LOX-aspartame" complex, that was predicted by docking studies, was further evaluated by Molecular Dynamics (MD) simulations in order to assess the stability of the complex. The binding energy of the complex has been calculated after MD simulations using Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) method. Furthermore, Quantum Mechanics/Molecular Mechanics (QM/MM) calculations have been applied for geometry optimization of the "enzyme-ligand" complex. After having fully characterized the "LOX-aspartame" complex in silico, followed in vitro biological assays confirmed that aspartame inhibits LOX-1 (IC50=50 ± 3.0 μΜ) and blocks its biological response. The atomic details of aspartame's interaction profile with LOX-1 were revealed through Saturation Transfer Difference (STD) NMR (Nuclear Magnetic Resonance). Finally, aspartame was also tested with Molecular Docking and Molecular Dynamics studies for its potent binding to a number of different LOX isoforms of many organisms, including human. The in silico methods indicated that aspartame could serve as a novel starting point for drug design against LOX enzyme. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Eleni Chontzopoulou
- Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Christina D Papaemmanouil
- Department of Chemistry, Section of Organic Chemistry and Biochemistry, University of Ioannina, Ioannina, Greece
| | - Maria V Chatziathanasiadou
- Department of Chemistry, Section of Organic Chemistry and Biochemistry, University of Ioannina, Ioannina, Greece
| | - Dimitrios Kolokouris
- Department of Pharmacy, National and Kapodistrian, University of Athens, Athens, Greece
| | - Sofia Kiriakidi
- Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Athina Konstantinidi
- Department of Pharmacy, National and Kapodistrian, University of Athens, Athens, Greece
| | - Ioanna Gerogianni
- Institute of Biology, Medicinal Chemistry and Biotechnology, Department of Pharmaceutical Chemistry, School of Pharmacy, Faculty of Health Sciences, National Hellenic Research Foundation, Athens, Greece.,Department of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | | | - Ioannis K Kostakis
- Department of Pharmacy, National and Kapodistrian, University of Athens, Athens, Greece
| | - Evangelia D Chrysina
- Institute of Biology, Medicinal Chemistry and Biotechnology, Department of Pharmaceutical Chemistry, School of Pharmacy, Faculty of Health Sciences, National Hellenic Research Foundation, Athens, Greece.,Department of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | | | - Demeter Tzeli
- Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Andreas G Tzakos
- Department of Chemistry, Section of Organic Chemistry and Biochemistry, University of Ioannina, Ioannina, Greece.,Institute of Materials Science and Computing, University Research Center of Ioannina (URCI), Ioannina, Greece
| | - Thomas Mavromoustakos
- Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
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14
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Ponnusamy V, Subramanian G, Muthuswamy K, Shanmugamprema D, Krishnan V, Velusamy T, Subramaniam S. Genetic variation in sweet taste receptors and a mechanistic perspective on sweet and fat taste sensation in the context of obesity. Obes Rev 2022; 23:e13512. [PMID: 36282093 DOI: 10.1111/obr.13512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/14/2022] [Accepted: 10/05/2022] [Indexed: 11/30/2022]
Abstract
Taste sensation enables humans to make nutritionally important decisions such as food preference and consumption. It functions as deterministic factors for unpropitious eating behavior, leading to overweight and obesity. The hedonistic feeling on consumption of fat and sugar-rich meals, in particular, has a negative influence on health. In addition, impairment in the taste receptors alters the downstream signaling of taste transduction pathway. Hence, genetic polymorphism in typical taste receptors is a predictor of taste sensitivity variance across individuals. The present review summarizes the effect of a single nucleotide polymorphism (SNP) in sweet taste receptors (T1R2/T1R3) on taste perception among individuals of various body mass index (BMI). Furthermore, in the context of obesity, we discussed the possibility of crosstalk between fat and sweet receptors as well as taste dysfunction in diseased individuals. In overall, a greater understanding of the physiological relationship between taste receptors, altered taste sensitivity, and genetic polymorphisms should lead to more effective obesity prevention approaches.
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Affiliation(s)
- Vinithra Ponnusamy
- Molecular Physiology Laboratory, Department of Biochemistry, Bharathiar University, Coimbatore, Tamilnadu, India, 641046
| | - Gowtham Subramanian
- Molecular Physiology Laboratory, Department of Biochemistry, Bharathiar University, Coimbatore, Tamilnadu, India, 641046
| | - Karthi Muthuswamy
- Molecular Physiology Laboratory, Department of Biochemistry, Bharathiar University, Coimbatore, Tamilnadu, India, 641046
| | - Deepankumar Shanmugamprema
- Molecular Physiology Laboratory, Department of Biochemistry, Bharathiar University, Coimbatore, Tamilnadu, India, 641046
| | - Vasanth Krishnan
- Molecular Biology Laboratory, Department of Botany, School of Life Sciences, Bharathiar University, Coimbatore, Tamilnadu, India, 641046
| | - Thirunavukkarasu Velusamy
- Department of Biotechnology, School of Biotechnology and Genetic Engineering, Bharathiar University, Coimbatore, Tamilnadu, India, 641046
| | - Selvakumar Subramaniam
- Molecular Physiology Laboratory, Department of Biochemistry, Bharathiar University, Coimbatore, Tamilnadu, India, 641046
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15
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Comparing the difference in enhancement of kokumi-tasting γ-glutamyl peptides on basic taste via molecular modeling approaches and sensory evaluation. FOOD SCIENCE AND HUMAN WELLNESS 2022. [DOI: 10.1016/j.fshw.2022.06.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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16
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Deck CM, Behrens M, Wendelin M, Ley JP, Krammer GE, Lieder B. Impact of lactisole on the time-intensity profile of selected sweeteners in dependence of the binding site. Food Chem X 2022; 15:100446. [PMID: 36211761 PMCID: PMC9532755 DOI: 10.1016/j.fochx.2022.100446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/30/2022] [Accepted: 09/12/2022] [Indexed: 10/25/2022] Open
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17
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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.
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18
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An updated multifaceted overview of sweet proteins and dipeptides as sugar substitutes; the chemistry, health benefits, gut interactions, and safety. Food Res Int 2022; 162:111853. [DOI: 10.1016/j.foodres.2022.111853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 08/13/2022] [Accepted: 08/21/2022] [Indexed: 11/24/2022]
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19
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Behavioral responses to sweet compounds via T1R2-independent pathways in chickens. Poult Sci 2022; 101:101928. [PMID: 35679679 PMCID: PMC9189227 DOI: 10.1016/j.psj.2022.101928] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 04/05/2022] [Accepted: 04/18/2022] [Indexed: 11/23/2022] Open
Abstract
Elucidating the taste sensing systems in chickens will enhance our understanding of poultry nutrition and improve the feeding strategies used in poultry farming. It is known that chickens lack the sweet taste receptor subunit, taste receptor type 1 member 2 (T1R2), in their genome. Thus, the present study investigated T1R2-independent sweet-sensing pathways in chickens. RT-PCR analysis revealed that glucose transporters known to play an important role in T1R2-independent sweet sensing in mammals—namely sodium-glucose cotransporter 1 (SGLT1) and ATP-gated K+ channel subunits—are expressed in the palate, the main taste organ in chickens. In behavioral tests, chickens slightly preferred glucose, galactose, sucrose, maltose, lactose, and stevioside, while high doses of sucrose and fructose were rejected. Chickens did not show any preference for noncaloric sweeteners or sugar alcohol, such as acesulfame K, aspartame, saccharin, sucralose, or sorbitol. The preference for galactose was inhibited by an inhibitor of SGLT1 in a dose-dependent manner. In addition, we found that glucagon-like peptide 1 (GLP-1) and mRNA of the GLP-1 receptor, which are involved specifically in sweet transmission in mice, are also present in the oral tissues of chickens. The present results imply that chickens can sense various sweet compounds via T1R2-independent pathways in oral tissues.
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20
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Dubovski N, Ben Shoshan-Galeczki Y, Malach E, Niv MY. Taste and chirality: l-glucose sweetness is mediated by TAS1R2/TAS2R3 receptor. Food Chem 2022; 373:131393. [PMID: 34715629 DOI: 10.1016/j.foodchem.2021.131393] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 09/27/2021] [Accepted: 10/09/2021] [Indexed: 01/14/2023]
Abstract
Naturally occurring sugars usually have d-chirality. While a change in chirality typically affects ligand-receptor interaction, non-caloric l-glucose was reported as sweet for humans. Here we show that l- and d-glucose have similar sensory detection thresholds (0.041 ± 0.006 M for d-glucose, and 0.032 ± 0.007 M for l-glucose) and similar sweetness intensities at suprathreshold concentrations. We demonstrate that l-glucose acts via the sweet taste receptor TAS1R2/TAS1R3, eliciting a dose-dependent activation in cell-based functional assays. Computational docking of glucose to the VFT domain of TAS1R2 suggests two sub-pockets, each compatible with each of the enantiomers. While some polar residues (Y103, D142, N143, S144, Y215) are unique for sub-pocket A and others (D307, T326, E382, R383) for sub-pocket B, no interaction is unique for only one enantiomer. The many options for creating hydrogen bonds with the hydroxyl moieties of glucose explain how both enantiomers can fit each one of the sub-pockets.
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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, P.O. Box 12, Rehovot 76100, Israel; Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, 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, P.O. Box 12, Rehovot 76100, Israel; Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, Israel.
| | - Einav Malach
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel; Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, 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, P.O. Box 12, Rehovot 76100, Israel; Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, Israel.
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21
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Martin LE, Lim J. OUP accepted manuscript. Chem Senses 2022; 47:6565984. [PMID: 35397161 PMCID: PMC8994581 DOI: 10.1093/chemse/bjac006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Oligosaccharides, a subclass of complex carbohydrates, occur both naturally in foods and as a result of oral starch digestion. We have previously shown that humans can taste maltooligosaccharides (MOS) and that their detection is independent of the canonical sweet taste receptor. While MOSs most commonly occur in a linear form, they can also exist in cyclic structures, referred to as cyclodextrins (CD). The aim of this study was to investigate how the structure of the MOS backbone (i.e. cyclic form) and the size (i.e. degree of polymerization; DP) affect their taste perception. We tested taste detection of cyclodextrins with DP of 6, 7, and 8 (i.e. α-, β-, and γ-CD, respectively) in the presence and absence of lactisole, a sweet receptor antagonist. We found that subjects could detect the taste of cyclodextrins in aqueous solutions at a significant level (P < 0.05), but were not able to detect them in the presence of lactisole (P > 0.05). These findings suggest that the cyclodextrins, unlike their linear analogs, are ligands of the human sweet taste receptor, hT1R2/hT1R3. Study findings are discussed in terms of how chemical structures may contribute to tastes of saccharides.
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Affiliation(s)
- Laura E Martin
- Department of Food Science and Technology, Oregon State University, Corvallis, OR 97331, USA
| | - Juyun Lim
- Department of Food Science and Technology, Oregon State University, Corvallis, OR 97331, USA
- Corresponding author: Department of Food Science and Technology, Oregon State University, 100 Wiegand Hall, Corvallis, OR 97331, USA.
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22
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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.
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23
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On the human taste perception: Molecular-level understanding empowered by computational methods. Trends Food Sci Technol 2021. [DOI: 10.1016/j.tifs.2021.07.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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24
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Aida H, Morita R, Shigeta Y, Harada R. In silico mutational analyses reveal different ligand-binding abilities of double pockets of medaka fish taste receptor type 1 essential for efficient taste recognition. Phys Chem Chem Phys 2021; 23:20398-20405. [PMID: 34494045 DOI: 10.1039/d1cp02876f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Taste receptors are important sensors for the detection of nutrient concentrations in animals. Tastes are recognized by interactions between chemical substances and taste receptors. Recently, the high-resolution X-ray crystal structure of the extracellular ligand-binding domains (LBDs) of medaka fish (Oryzias latipes) taste receptor type 1 (T1r) complexed with ligands (amino acids) was determined. Medaka fish T1r is a heterodimer composed of two different LBDs, T1r2aLBD and T1r3LBD. In this study, we performed all-atom molecular dynamics (MD) simulations on this heterodimer (T1r2aLBD-T1r3LBD) to address mutational effects on key residues near each ligand-binding pocket in recognizing one of the ligands (L-Gln). For T1r2aLBD, Ser165 is important in ligand recognition due to its direct hydrogen bonding with the ligand. After mutating Ser165 to Ile or Ala, the direct hydrogen bonds between the ligand and the binding pocket were weakened, which destabilized the ligand-binding form of T1r2aLBD. For T1r3LBD, Ser300 is important in ligand recognition. The water-mediated hydrogen bond with the side-chain hydroxyl group of Ser300 is a single interaction that maintains the ligand-binding form of T1r3LBD. After mutating Ser300 to Glu or Ala, both mutant systems almost maintained their ligand-binding form. As a mechanism for maintaining the binding form of T1r3LBD, alternative hydrogen bonds were formed as direct interactions instead of the indirect water-mediated interactions found in the wild-type system, which stabilized the binding form of T1r3LBD. Judging from our in silico mutational analyses, T1r2aLBD was structurally destabilized by the amino acid mutations. Therefore, it might be required that the ligand-binding pocket of T1r2aLBD is composed of a set of specific residues to maintain its ligand-binding form. On the contrary, T1r3LBD was robust enough to withstand the amino acid mutations. These different ligand-binding abilities of both LBDs provide multiple binding modes, which might be helpful for discriminating various taste substances or detecting concentrations of nutrients efficiently.
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Affiliation(s)
- Hayato Aida
- Master's Program in Biology, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan.
| | - Rikuri Morita
- Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Yasuteru Shigeta
- Master's Program in Biology, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan. .,Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Ryuhei Harada
- Master's Program in Biology, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan. .,Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
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25
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Zhao X, Wang C, Zheng Y, Liu B. New Insight Into the Structure-Activity Relationship of Sweet-Tasting Proteins: Protein Sector and Its Role for Sweet Properties. Front Nutr 2021; 8:691368. [PMID: 34222309 PMCID: PMC8249704 DOI: 10.3389/fnut.2021.691368] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 05/18/2021] [Indexed: 12/28/2022] Open
Abstract
Sweet-tasting protein is a kind of biomacromolecule that has remarkable sweetening power and is regarded as the promising sugar replacer in the future. Some sweet-tasting proteins has been used in foods and beverages. However, the structure and function relationship of these proteins is still elusive, and guidelines for their protein engineering is limited. It is well-known that the sweet-tasting proteins bind to and activate the sweet taste receptor T1R2/T1R3, thus eliciting their sweetness. The “wedge-model” for describing the interaction between sweet-tasting proteins and sweet taste receptor to elucidate their sweetness has been reported. In this perspective article, we revealed that the intramolecular interaction forces in sweet-tasting proteins is directly correlated to their properties (sweetness and stability). This intramolecular interaction pattern, named as “protein sector,” refers to a small subset of residues forming physically connections, which cooperatively affect the function of the proteins. Based on the analysis of previous experimental data, we suggest that “protein sector” of sweet-tasting proteins is pivotal for their sweet properties, which are meaningful guidelines for the future protein engineering.
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Affiliation(s)
- Xiangzhong Zhao
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Congrui Wang
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Yue Zheng
- Shandong Aojing Biotechnology Co., Ltd., Zoucheng, China
| | - Bo Liu
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
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26
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Nakagita T, Taketani C, Narukawa M, Hirokawa T, Kobayashi T, Misaka T. Ibuprofen, a Nonsteroidal Anti-Inflammatory Drug, is a Potent Inhibitor of the Human Sweet Taste Receptor. Chem Senses 2021; 45:667-673. [PMID: 32832995 DOI: 10.1093/chemse/bjaa057] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A sweet taste receptor is composed of heterodimeric G-protein-coupled receptors T1R2 and T1R3. Although there are many sweet tastants, only a few compounds have been reported as negative allosteric modulators (NAMs), such as lactisole, its structural derivative 2,4-DP, and gymnemic acid. In this study, candidates for NAMs of the sweet taste receptor were explored, focusing on the structural motif of lactisole. Ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), has an α-methylacetic acid moiety, and this structure is also shared by lactisole and 2,4-DP. When ibuprofen was applied together with 1 mM aspartame to the cells that stably expressed the sweet taste receptor, it inhibited the receptor activity in a dose-dependent manner. The IC50 value of ibuprofen against the human sweet taste receptor was calculated as approximately 12 μM, and it was almost equal to that of 2,4-DP, which is known as the most potent NAM for the receptor to date. On the other hand, when the inhibitory activities of other profens were examined, naproxen also showed relatively potent NAM activity against the receptor. The results from both mutant analysis for the transmembrane domain (TMD) of T1R3 and docking simulation strongly suggest that ibuprofen and naproxen interact with T1R3-TMD, similar to lactisole and 2,4-DP. However, although 2,4-DP and ibuprofen had almost the same inhibitory activities, these activities were acquired by filling different spaces of the ligand pocket of T1R3-TMD; this knowledge could lead to the rational design of a novel NAM against the sweet taste receptor.
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Affiliation(s)
- Tomoya Nakagita
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan.,Department of Cell Biology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, Japan.,Proteo-Science Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime, Japan
| | - Chiaki Taketani
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Masataka Narukawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Takatsugu Hirokawa
- Molecular Profiling Research Center for Drug Discovery, National Institutes of Advanced Industrial Science and Technology, Aomi, Koto-ku, Tokyo, Japan.,Department of Chemical Biology, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan
| | - Takuya Kobayashi
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, Japan
| | - Takumi Misaka
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
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27
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Aspartame induces cancer stem cell enrichment through p21, NICD and GLI1 in human PANC-1 pancreas adenocarcinoma cells. Food Chem Toxicol 2021; 153:112264. [PMID: 33992720 DOI: 10.1016/j.fct.2021.112264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 04/30/2021] [Accepted: 05/10/2021] [Indexed: 11/21/2022]
Abstract
This study aimed to investigate the molecular effects of the common natural sugar glucose and artificial sweetener aspartame on cancer stem cell (CSC) population and cancer aggressiveness of PANC-1 human pancreas adenocarcinoma cells. According to our findings while aspartame exposure significantly increased the CSC population, high glucose had no effect on it. The epithelial-mesenchymal transition marker N-cadherin increased only in the aspartame group. The findings indicate that a high level of glucose exposure does not effect the invasion and migration of PANC-1 cells, while aspartame increases both of these aggressiveness criteria. The findings also suggest that a high concentration of glucose maintains CSC population through induction of nuclear Oct3/4 and differentiation to parental cells via increasing cytoplasmic c-myc. Aspartame exposure to PANC-1 cells activated AKT and deactivated GSK3β by increasing levels of ROS and cytoplasmic Ca+2, respectively, through T1R2/T1R3 stimulation. Then p-GSK3β(Ser9) boosted the CSC population by increasing pluripotency factors Oct3/4 and c-myc via NICD, GLI1 and p21. In the aspartame group, T1R1 silencing further increased the CSC population but decreased cell viability and suppressed the p21, NICD and GLI activation. The presence and amount of T1R subunits in the membrane fraction of PANC-1 cells are demonstrated for the first time in this study, as is the regulatory effect of T1R1's on CSC population. In conclusion, the present study demonstrated that long-term aspartame exposure increases CSC population and tumor cell aggressiveness through p21, NICD, GLI1. Moreover, while aspartame had no tumorigenic effect, it could potentially advance an existing tumor.
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Smith NJ, Grant JN, Moon JI, So SS, Finch AM. Critically evaluating sweet taste receptor expression and signaling through a molecular pharmacology lens. FEBS J 2021; 288:2660-2672. [DOI: 10.1111/febs.15768] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/04/2021] [Accepted: 02/15/2021] [Indexed: 12/26/2022]
Affiliation(s)
- Nicola J. Smith
- Orphan Receptor Laboratory School of Medical Sciences UNSW Sydney Kensington Australia
| | - Jennifer N. Grant
- Orphan Receptor Laboratory School of Medical Sciences UNSW Sydney Kensington Australia
- G Protein‐Coupled Receptor Laboratory School of Medical Sciences UNSW Sydney Kensington Australia
| | - Justin I. Moon
- Orphan Receptor Laboratory School of Medical Sciences UNSW Sydney Kensington Australia
- G Protein‐Coupled Receptor Laboratory School of Medical Sciences UNSW Sydney Kensington Australia
| | - Sean S. So
- Orphan Receptor Laboratory School of Medical Sciences UNSW Sydney Kensington Australia
| | - Angela M. Finch
- G Protein‐Coupled Receptor Laboratory School of Medical Sciences UNSW Sydney Kensington Australia
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29
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Daly K, Moran AW, Al-Rammahi M, Weatherburn D, Shirazi-Beechey SP. Non-nutritive sweetener activation of the pig sweet taste receptor T1R2-T1R3 in vitro mirrors sweetener stimulation of the gut-expressed receptor in vivo. Biochem Biophys Res Commun 2021; 542:54-58. [PMID: 33486192 DOI: 10.1016/j.bbrc.2021.01.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/12/2021] [Indexed: 10/22/2022]
Abstract
The perception of sweet is mediated by the sweet taste receptor T1R2-T1R3 expressed in taste cells of the lingual epithelium. This receptor is also expressed in intestinal enteroendocrine cells and is required for sensing luminal sugars and sweeteners to regulate expression of intestinal Na+-glucose cotransporter 1 (SGLT1). There are some notable differences amongst species in the ability to detect certain non-nutritive (artificial) sweeteners. Amino acid substitutions and pseudogenization of taste receptor genes are responsible for these disparities. Using heterologous expression, we demonstrate that the commonly used non-nutritive sweeteners sucralose, saccharin and acesulfame K activate pig T1R2-T1R3, but that aspartame and cyclamate do not. Furthermore, we show that in vitro sweetener activation of pig T1R2-T1R3 mirrors the sweetener stimulation of the gut-expressed receptor in vivo. Considering that sweeteners are included in animal feed worldwide, determination of taste receptor specificities in different species is essential for the development of scientifically-based dietary formulations.
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Affiliation(s)
- Kristian Daly
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Andrew W Moran
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Miran Al-Rammahi
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK; Department of Physiology, Biochemistry and Pharmacology, College of Veterinary Medicine, University of Al-Qadisiyah, Al-Diwaniyah, 58002, Iraq
| | - Darren Weatherburn
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Soraya P Shirazi-Beechey
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK.
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30
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Koh W, Lim H, Chen X. Atypical triggers in trigeminal neuralgia: the role of A-delta sensory afferents in food and weather triggers. Korean J Pain 2021; 34:66-71. [PMID: 33380569 PMCID: PMC7783845 DOI: 10.3344/kjp.2021.34.1.66] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 11/05/2022] Open
Abstract
Background Trigeminal neuralgia is a debilitating craniofacial pain syndrome that is characterized by paroxysms of intense, short-lived electric shock-like pains in the trigeminal nerve distribution. Recently, the presence of triggers has become one of the key diagnostic criteria in the 3rd edition of the International Classification of Headache Disorders. Light touch is the most common trigger, however other non-mechanical triggers, such as cold weather and certain foods, have been thought to provoke trigeminal neuralgia anecdotally. We aimed to characterize the prevalence and characteristics of these atypical triggers. Methods We conducted a retrospective, cross-sectional study of atypical triggers in trigeminal neuralgia patients seen in a tertiary pain clinic in Singapore. Patients were recruited via clinic records, and study data were identified from physician documentation. Results A total of 60 patients met the inclusion criteria. Weather triggers were observed in 12 patients (20%), of which five patients (8%) reported strong winds, 4 patients (7%) reported cold temperatures, and 3 patients (5%) reported cold winds as triggers. Fifteen patients (25%) had a specific food trigger, of which 10 patients (17%) reported hard or tough food, 5 patients (8%) reported hot/cold food, 4 patients (7%) reported spicy food, and 2 patients (3%) reported sweet food as triggers. Conclusions Although trigeminal neuralgia is most commonly triggered by mechanical stimuli, atypical triggers such as cold temperatures and certain foods are seen in a significant proportion of patients. These atypical triggers may share a common pathway of sensory afferent Aδ fiber activation.
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Affiliation(s)
- Wenjun Koh
- Department of Anaesthesiology, Singapore General Hospital, Singapore
| | - Huili Lim
- Department of Anaesthesiology, Singapore General Hospital, Singapore
| | - Xuanxuan Chen
- Department of Anaesthesiology, Singapore General Hospital, Singapore
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31
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Matsumoto R, Yamada K, Nakazawa M, Mori S, Kitajima S. Structure–Activity Relationship Study of T1R2/T1R3 Positive Allosteric Modulators and Evaluation of Their Enhancing Effect on Various Sweeteners. ChemistrySelect 2020. [DOI: 10.1002/slct.202002159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Ryo Matsumoto
- Ajinomoto Co., Inc., 1–1, Suzuki-Cho Kawasaki-Ku Kawasaki-Shi 210-8681 Japan
| | - Kei Yamada
- Ajinomoto Co., Inc., 1–1, Suzuki-Cho Kawasaki-Ku Kawasaki-Shi 210-8681 Japan
| | - Masakazu Nakazawa
- Ajinomoto Co., Inc., 1–1, Suzuki-Cho Kawasaki-Ku Kawasaki-Shi 210-8681 Japan
| | - Suguru Mori
- Ajinomoto Co., Inc., 1–1, Suzuki-Cho Kawasaki-Ku Kawasaki-Shi 210-8681 Japan
| | - Seiji Kitajima
- Ajinomoto Co., Inc., 1–1, Suzuki-Cho Kawasaki-Ku Kawasaki-Shi 210-8681 Japan
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32
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Mahalapbutr P, Lee VS, Rungrotmongkol T. Binding Hotspot and Activation Mechanism of Maltitol and Lactitol toward the Human Sweet Taste Receptor. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:7974-7983. [PMID: 32551626 DOI: 10.1021/acs.jafc.0c02580] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Human sweet taste receptor (hSTR) recognizes a wide array of sweeteners, resulting in sweet taste perception. Maltitol and lactitol have been extensively used in place of sucrose due to their capability to prevent dental caries. Herein, several molecular modeling approaches were applied to investigate the structural and energetic properties of these two polyols/hSTR complexes. Triplicate 500 ns molecular dynamics (MD) simulations and molecular mechanics/generalized Born surface area (MM/GBSA)-based free energy calculations revealed that the TAS1R2 monomer is the preferential binding site for maltitol and lactitol rather than the TAS1R3 region. Several polar residues (D142, S144, Y215, D278, E302, R383, and especially N143) were involved in polyols binding through electrostatic attractions and H-bond formations. The molecular complexation process not only induced the stable form of ligands but also stimulated the conformational adaptation of the TAS1R2 monomer to become a close-packed structure through an induced-fit mechanism. Notably, the binding affinity of the maltitol/TAS1R2 complex (ΔGbind of -17.93 ± 1.49 kcal/mol) was significantly higher than that of the lactitol/TAS1R2 system (-8.53 ± 1.78 kcal/mol), in line with the experimental relative sweetness. These findings provide an in-depth understanding of the differences in the sweetness response between maltitol and lactitol, which could be helpful to design novel polyol derivatives with higher sweet taste perception.
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Affiliation(s)
- Panupong Mahalapbutr
- Biocatalyst and Environmental Biotechnology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Vannajan Sanghiran Lee
- Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Thanyada Rungrotmongkol
- Biocatalyst and Environmental Biotechnology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
- Program in Bioinformatics and Computational Biology, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand
- Molecular Sensory Science Center, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
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33
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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: 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.
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34
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Structure-based screening for discovery of sweet compounds. Food Chem 2020; 315:126286. [DOI: 10.1016/j.foodchem.2020.126286] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/10/2020] [Accepted: 01/21/2020] [Indexed: 02/06/2023]
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35
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The function and allosteric control of the human sweet taste receptor. FROM STRUCTURE TO CLINICAL DEVELOPMENT: ALLOSTERIC MODULATION OF G PROTEIN-COUPLED RECEPTORS 2020; 88:59-82. [DOI: 10.1016/bs.apha.2020.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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36
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Chen Z, Xu X, Piao L, Chang S, Liu J, Kong R. Identify old drugs as selective bacterial β-GUS inhibitors by structural-based virtual screening and bio-evaluations. Chem Biol Drug Des 2019; 95:368-379. [PMID: 31834987 DOI: 10.1111/cbdd.13655] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/02/2019] [Accepted: 12/07/2019] [Indexed: 01/18/2023]
Abstract
Irinotecan (CPT-11) is a cytotoxic drug that has wide applicability and usage in cancer treatment. Despite its success, patients suffer dose-dependent diarrhea, limiting the drug's efficacy. No effective therapy is available for this unmet medical need. The bacterial β-glucuronidase (β-GUS) plays pivotal role in CPT-11-induced diarrhea (CID) via activating the non-toxic SN-38G to toxic SN-38 inside intestine. By using structural-based virtual screening, three old drugs (N-Desmethylclozapine, Aspartame, and Gemifloxacin) were firstly identified as selective bacterial β-GUS inhibitors. The IC50 values of the compounds in the enzyme-based and cell-based assays range from 0.0389 to 3.6040 and 0.0105 to 5.3730 μM, respectively. The compounds also showed good selectivity against mammalian β-GUS and no significant cytotoxicity in bacteria. Molecular docking and molecular dynamics simulations were performed to further investigate the binding modes of compounds with bacterial β-GUS. Binding free energy decomposition revealed that the compounds formed strong interactions with E413 in catalytic trail from primary monomer and F365' on the bacterial loop from the other monomer of bacterial β-GUS, explaining the selectivity against mammalian β-GUS. The old drugs identified here may be used as bacterial β-GUS inhibitors for CID or other bacterial β-GUS-related disorders.
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Affiliation(s)
- Zhou Chen
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, School of Chemical and Environmental Engineering, Jiangsu University of Technology, Changzhou, China
| | - Xiaoshuang Xu
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, School of Chemical and Environmental Engineering, Jiangsu University of Technology, Changzhou, China
| | - Lianhua Piao
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, School of Chemical and Environmental Engineering, Jiangsu University of Technology, Changzhou, China
| | - Shan Chang
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, School of Chemical and Environmental Engineering, Jiangsu University of Technology, Changzhou, China
| | - Jiyong Liu
- Department of Pharmacy, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Ren Kong
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, School of Chemical and Environmental Engineering, Jiangsu University of Technology, Changzhou, China
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37
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Kashani-Amin E, Sakhteman A, Larijani B, Ebrahim-Habibi A. Presence of carbohydrate binding modules in extracellular region of class C G-protein coupled receptors (C GPCR): An in silico investigation on sweet taste receptor. J Biosci 2019; 44:138. [PMID: 31894119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Sweet taste receptor (STR) is a C GPCR family member and a suggested drug target for metabolic disorders such as diabetes. Detailed characteristics of the molecule as well as its ligand interactions mode are yet considerably unclear due to experimental study limitations of transmembrane proteins. An in silico study was designed to find the putative carbohydrate binding sites on STR. To this end, α-D-glucose and its α-1,4-oligomers (degree of polymerization up to 14) were chosen as probes and docked into an ensemble of different conformations of the extracellular region of STR monomers (T1R2 and T1R3), using AutoDock Vina. Ensembles had been sampled from an MD simulation experiment. Best poses were further energy-minimized in the presence of water molecules with Amber14 forcefield. For each monomer, four distinct binding regions consisting of one or two binding pockets could be distinguished. These regions were further investigated with regard to hydrophobicity and hydrophilicity of the residues, as well as residue compositions and non-covalent interactions with ligands. Popular binding regions showed similar characteristics to carbohydrate binding modules (CBM). Observation of several conserved or semi-conserved residues in these binding regions suggests a possibility to extrapolate the results to other C GPCR family members. In conclusion, presence of CBM in STR and, by extrapolation, in other C GPCR family members is suggested, similar to previously proposed sites in gut fungal C GPCRs, through transcriptome analyses. STR modes of interaction with carbohydrates are also discussed and characteristics of non-covalent interactions in C GPCR family are highlighted.
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Affiliation(s)
- Elaheh Kashani-Amin
- Biosensor Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
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38
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Presence of carbohydrate binding modules in extracellular region of class C G-protein coupled receptors (C GPCR): An in silico investigation on sweet taste receptor. J Biosci 2019. [DOI: 10.1007/s12038-019-9944-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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39
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Reyes MM, Gravina SA, Hayes JE. Evaluation of Sweetener Synergy in Humans by Isobole Analyses. Chem Senses 2019; 44:571-582. [PMID: 31424498 DOI: 10.1093/chemse/bjz056] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The chemical senses and pharmaceuticals fundamentally depend on similar biological processes, but novel molecule discovery has classically been approached from vastly different vantage points. From the perspective of ingredient and flavor companies, there are countless ingredients that act via largely unknown mechanisms, whereas the pharmaceutical industry has numerous mechanisms in search of novel compounds. Mixtures of agonists can result in synergistic (superadditive) responses, which can be quantified via isobole analysis, a well-proven clinical approach in pharmacology. For the food and beverage industries, bulk (caloric) sweeteners like sugars are a key ingredient in sweetened foods and beverages, but consumers also desire products with fewer calories, which has led to the development of sweet enhancers and sweetener blends intended to achieve synergy or superadditivity. Synergistic mixtures are highly attractive targets commercially as they enable lower usage levels and enhanced efficacy. Although the psychophysical literature contains numerous prior reports of sweetener synergy, others have also noted that classical additive models fail to account for nonlinear dose-response functions. To address this shortcoming, here we systematically apply the isobole method from pharmacology to quantify the presence or absence of psychophysical synergy for binary pairs of sweeteners in a series of 15 separate experiments, each with ~100 adult volunteers (total n = 1576). Generally, these data support the hypothesis that structurally similar sweeteners acting as agonists will not synergize, whereas structurally dissimilar sweeteners binding to overlapping or distal sites can act as allosteric agonists or agonist-antagonists, respectively.
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Affiliation(s)
- M Michelle Reyes
- Sensory Evaluation Center, The Pennsylvania State University, University Park, PA, USA.,Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA, USA
| | | | - John E Hayes
- Sensory Evaluation Center, The Pennsylvania State University, University Park, PA, USA.,Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA, USA
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40
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Mahalapbutr P, Darai N, Panman W, Opasmahakul A, Kungwan N, Hannongbua S, Rungrotmongkol T. Atomistic mechanisms underlying the activation of the G protein-coupled sweet receptor heterodimer by sugar alcohol recognition. Sci Rep 2019; 9:10205. [PMID: 31308429 PMCID: PMC6629994 DOI: 10.1038/s41598-019-46668-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/03/2019] [Indexed: 12/03/2022] Open
Abstract
The human T1R2-T1R3 sweet taste receptor (STR) plays an important role in recognizing various low-molecular-weight sweet-tasting sugars and proteins, resulting in the release of intracellular heterotrimeric G protein that in turn leads to the sweet taste perception. Xylitol and sorbitol, which are naturally occurring sugar alcohols (polyols) found in many fruits and vegetables, exhibit the potential caries-reducing effect and are widely used for diabetic patients as low-calorie sweeteners. In the present study, computational tools were applied to investigate the structural details of binary complexes formed between these two polyols and the T1R2-T1R3 heterodimeric STR. Principal component analysis revealed that the Venus flytrap domain (VFD) of T1R2 monomer was adapted by the induced-fit mechanism to accommodate the focused polyols, in which α-helical residues 233-268 moved significantly closer to stabilize ligands. This finding likely suggested that these structural transformations might be the important mechanisms underlying polyols-STR recognitions. The calculated free energies also supported the VFD of T1R2 monomer as the preferential binding site for such polyols, rather than T1R3 region, in accord with the lower number of accessible water molecules in the T1R2 pocket. The E302 amino acid residue in T1R2 was found to be the important recognition residue for polyols binding through a strongly formed hydrogen bond. Additionally, the binding affinity of xylitol toward the T1R2 monomer was significantly higher than that of sorbitol, making it a sweeter tasting molecule.
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Affiliation(s)
- Panupong Mahalapbutr
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Nitchakan Darai
- Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Wanwisa Panman
- Multidisciplinary Program of Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Aunchan Opasmahakul
- Computational Chemistry Center of Excellent, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Nawee Kungwan
- Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
- Center of Excellence in Materials Science and Technology, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Supot Hannongbua
- Computational Chemistry Center of Excellent, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Thanyada Rungrotmongkol
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
- Ph.D. Program in Bioinformatics and Computational Biology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
- Molecular Sensory Science Center, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
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41
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Kashani-Amin E, Sakhteman A, Larijani B, Ebrahim-Habibi A. Introducing a New Model of Sweet Taste Receptor, a Class C G-protein Coupled Receptor (C GPCR). Cell Biochem Biophys 2019; 77:227-243. [PMID: 31069640 DOI: 10.1007/s12013-019-00872-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 04/27/2019] [Indexed: 12/31/2022]
Abstract
The structure of sweet taste receptor (STR), a heterodimer of class C G-protein coupled receptors comprising T1R2 and T1R3 molecules, is still undetermined. In this study, a new enhanced model of the receptor is introduced based on the most recent templates. The improvement, stability, and reliability of the model are discussed in details. Each domain of the protein, i.e., VFTM, CR, and TMD, were separately constructed by hybrid-model construction methods and then assembled to build whole monomers. Overall, 680 ns molecular dynamics simulation was performed for the individual domains, the whole monomers and the heterodimer form of the VFTM orthosteric binding site. The latter's structure obtained from 200 ns simulation was docked with aspartame; among various binding sites suggested by FTMAP server, the experimentally suggested binding domain in T1R2 was retrieved. Local three-dimensional structures and helices spans were evaluated and showed acceptable accordance with the template structures and secondary structure predictions. Individual domains and whole monomer structures were found stable and reliable to be used. In conclusion, several validations have shown reliability of the new and enhanced models for further molecular modeling studies on structure and function of STR and C GPCRs.
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Affiliation(s)
- Elaheh Kashani-Amin
- Biosensor Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Amirhossein Sakhteman
- Department of Medicinal Chemistry, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.,Medicinal Chemistry and Natural Products Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Bagher Larijani
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Azadeh Ebrahim-Habibi
- Biosensor Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
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42
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Nakagita T, Ishida A, Matsuya T, Kobayashi T, Narukawa M, Hirokawa T, Hashimoto M, Misaka T. Structural insights into the differences among lactisole derivatives in inhibitory mechanisms against the human sweet taste receptor. PLoS One 2019; 14:e0213552. [PMID: 30883570 PMCID: PMC6422327 DOI: 10.1371/journal.pone.0213552] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 02/23/2019] [Indexed: 11/22/2022] Open
Abstract
Lactisole, an inhibitor of the human sweet taste receptor, has a 2-phenoxypropionic acid skeleton and has been shown to interact with the transmembrane domain of the T1R3 subunit (T1R3-TMD) of the receptor. Another inhibitor, 2,4-DP, which shares the same molecular skeleton as lactisole, was confirmed to be approximately 10-fold more potent in its inhibitory activity than lactisole; however the structural basis of their inhibitory mechanisms against the receptor remains to be elucidated. Crystal structures of the TMD of metabotropic glutamate receptors, which along with T1Rs are categorized as class C G-protein coupled receptors, have recently been reported and made it possible to create an accurate structural model for T1R3-TMD. In this study, the detailed structural mechanism underlying sweet taste inhibition was characterized by comparing the action of lactisole on T1R3-TMD with that of 2,4-DP. We first performed a series of experiments using cultured cells expressing the sweet taste receptor with mutations and examined the interactions with these inhibitors. Based on the results, we next performed docking simulations and then applied molecular dynamics-based energy minimization. Our analyses clearly revealed that the (S)-isomers of both lactisole and 2,4-DP, interacted with the same seven residues in T1R3-TMD and that the inhibitory potencies of those inhibitors were mainly due to stabilizing interactions mediated via their carboxyl groups in the vertical dimension of the ligand pocket of T1R3-TMD. In addition, 2,4-DP engaged in a hydrophobic interaction mediated by its o-Cl group, and this interaction may be chiefly responsible for the higher inhibitory potency of 2,4-DP.
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Affiliation(s)
- Tomoya Nakagita
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akiko Ishida
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Takumi Matsuya
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Takuya Kobayashi
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masataka Narukawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Takatsugu Hirokawa
- Molecular Profiling Research Center for Drug Discovery, National Institutes of Advanced Industrial Science and Technology, Tokyo, Japan
- Department of Chemical Biology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Makoto Hashimoto
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Takumi Misaka
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
- * E-mail:
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43
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Park J, Selvam B, Sanematsu K, Shigemura N, Shukla D, Procko E. Structural architecture of a dimeric class C GPCR based on co-trafficking of sweet taste receptor subunits. J Biol Chem 2019; 294:4759-4774. [PMID: 30723160 DOI: 10.1074/jbc.ra118.006173] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 01/24/2019] [Indexed: 01/06/2023] Open
Abstract
Class C G protein-coupled receptors (GPCRs) are obligatory dimers that are particularly important for neuronal responses to endogenous and environmental stimuli. Ligand recognition through large extracellular domains leads to the reorganization of transmembrane regions to activate G protein signaling. Although structures of individual domains are known, the complete architecture of a class C GPCR and the mechanism of interdomain coupling during receptor activation are unclear. By screening a mutagenesis library of the human class C sweet taste receptor subunit T1R2, we enhanced surface expression and identified a dibasic intracellular retention motif that modulates surface expression and co-trafficking with its heterodimeric partner T1R3. Using a highly expressed T1R2 variant, dimerization sites along the entire subunit within all the structural domains were identified by a comprehensive mutational scan for co-trafficking with T1R3 in human cells. The data further reveal that the C terminus of the extracellular cysteine-rich domain needs to be properly folded for T1R3 dimerization and co-trafficking, but not for surface expression of T1R2 alone. These results guided the modeling of the T1R2-T1R3 dimer in living cells, which predicts a twisted arrangement of domains around the central axis, and a continuous folded structure between transmembrane domain loops and the cysteine-rich domains. These insights have implications for how conformational changes between domains are coupled within class C GPCRs.
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Affiliation(s)
- Jihye Park
- From the Departments of Biochemistry and
| | - Balaji Selvam
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
| | - Keisuke Sanematsu
- the Section of Oral Neuroscience, Graduate School of Dental Science, and.,the Division of Sensory Physiology-Medical Application Sensing, Research and Development Center for Five-Sense Devices, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Noriatsu Shigemura
- the Section of Oral Neuroscience, Graduate School of Dental Science, and.,the Division of Sensory Physiology-Medical Application Sensing, Research and Development Center for Five-Sense Devices, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Diwakar Shukla
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
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Abstract
The study of taste has been guided throughout much of its history by the conceptual framework of psychophysics, where the focus was on quantification of the subjective experience of the taste sensations. By the mid-20th century, data from physiologic studies had accumulated sufficiently to assemble a model for the function of receptors that must mediate the initial stimulus of tastant molecules in contact with the tongue. But the study of taste as a receptor-mediated event did not gain momentum until decades later when the actual receptor proteins and attendant signaling mechanisms were identified and localized to the highly specialized taste-responsive cells of the tongue. With those discoveries a new opportunity to examine taste as a function of receptor activity has come into focus. Pharmacology is the science designed specifically for the experimental interrogation and quantitative characterization of receptor function at all levels of inquiry from molecules to behavior. This review covers the history of some of the major concepts that have shaped thinking and experimental approaches to taste, the seminal discoveries that have led to elucidation of receptors for taste, and how applying principles of receptor pharmacology can enhance understanding of the mechanisms of taste physiology and perception.
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Affiliation(s)
- R Kyle Palmer
- Opertech Bio, Inc., Pennovation Center, Philadelphia, Pennsylvania
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45
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Küçükbay H, Buğday N, Küçükbay FZ, Berrino E, Bartolucci G, Del Prete S, Capasso C, Supuran CT. Synthesis and carbonic anhydrase inhibitory properties of novel 4-(2-aminoethyl)benzenesulfonamide-dipeptide conjugates. Bioorg Chem 2018; 83:414-423. [PMID: 30419497 DOI: 10.1016/j.bioorg.2018.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/01/2018] [Accepted: 11/02/2018] [Indexed: 12/22/2022]
Abstract
Thirty novel sulfonamide derivatives incorporating dipeptide were synthesized by facile acylation through benzotriazole mediated reactions and their structures were identified by 1H NMR, 13C NMR, MS and FT-IR spectroscopic techniques and elemental analysis. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against four human (h) isoforms, hCA I, hCA II, hCA IV and hCA XII. Most of the synthesized compounds showed excellent in vitro carbonic anhydrase inhibitory properties comparable to those of the clinically used drug acetazolamide (AAZ). The new unprotected dipeptide-sulfonamide conjugates showed very effective inhibitory activity, in the low nanomolar range against II and XII, being less effective as hCA I and IV inhibitors. Four of the thirty compounds also showed strong inhibitory activity against hCA XII compared to AAZ.
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Affiliation(s)
- Hasan Küçükbay
- İnönü University, Faculty of Arts and Sciences, Department of Chemistry, 44280 Malatya, Turkey.
| | - Nesrin Buğday
- İnönü University, Faculty of Arts and Sciences, Department of Chemistry, 44280 Malatya, Turkey
| | - F Zehra Küçükbay
- İnönü University, Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, 44280 Malatya, Turkey
| | - Emanuela Berrino
- Dipartimento Neurofarba, Sezione Di Scienze Farmaceutiche E Nutraceutiche e Laboratorio Di Chimica Bioinorganica, Universita' Degli Studi Di Firenze, Sesto Fiorentino, Florence, Italy
| | - Gianluca Bartolucci
- Dipartimento Neurofarba, Sezione Di Scienze Farmaceutiche E Nutraceutiche e Laboratorio Di Chimica Bioinorganica, Universita' Degli Studi Di Firenze, Sesto Fiorentino, Florence, Italy
| | - Sonia Del Prete
- Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 111, Napoli, Italy
| | - Clemente Capasso
- Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 111, Napoli, Italy
| | - Claudiu T Supuran
- Dipartimento Neurofarba, Sezione Di Scienze Farmaceutiche E Nutraceutiche e Laboratorio Di Chimica Bioinorganica, Universita' Degli Studi Di Firenze, Sesto Fiorentino, Florence, Italy.
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46
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Glendinning JI. Oral Post-Oral Actions of Low-Calorie Sweeteners: A Tale of Contradictions and Controversies. Obesity (Silver Spring) 2018; 26 Suppl 3:S9-S17. [PMID: 30290077 DOI: 10.1002/oby.22253] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 05/28/2018] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Many scientists and laypeople alike have concerns about low-calorie sweeteners (LCSs). These concerns stem from both a dissatisfaction with the taste of LCSs and reports that they cause metabolic disruptions (e.g., weight gain, glucose intolerance). METHODS This article provides a critical review of the literature on LCSs from the standpoint of their taste, gastrointestinal, and metabolic effects; biological fate in the body; and impact on ingestion and glucose homeostasis. RESULTS AND CONCLUSIONS Mammals can readily discriminate between LCSs and sugars because both types of sweetener activate distinct oral and post-oral sensory pathways. LCSs differ in their ability to access post-oral tissues, but few studies have incorporated this observation into their design. It is difficult to extrapolate results between mice, rats, and humans because of interspecies differences in the taste and post-oral actions of LCSs and the fact that investigators often use different response measures in rodents and humans. There is confounding in the experimental design of some of the most widely cited studies of LCS-induced metabolic disruptions. The uncritical acceptance of these studies has generated considerable controversy. More work is needed to obtain a clearer understanding of the metabolic effects of LCSs.
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Affiliation(s)
- John I Glendinning
- Department of Biology, Barnard College, Columbia University, New York, New York, USA
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47
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Di Pizio A, Ben Shoshan-Galeczki Y, Hayes JE, Niv MY. Bitter and sweet tasting molecules: It's complicated. Neurosci Lett 2018; 700:56-63. [PMID: 29679682 DOI: 10.1016/j.neulet.2018.04.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/22/2018] [Accepted: 04/16/2018] [Indexed: 12/12/2022]
Abstract
"Bitter" and "sweet" are frequently framed in opposition, both functionally and metaphorically, in regard to affective responses, emotion, and nutrition. This oppositional relationship is complicated by the fact that some molecules are simultaneously bitter and sweet. In some cases, a small chemical modification, or a chirality switch, flips the taste from sweet to bitter. Molecules humans describe as bitter are recognized by a 25-member subfamily of class A G-protein coupled receptors (GPCRs) known as TAS2Rs. Molecules humans describe as sweet are recognized by a TAS1R2/TAS1R3 heterodimer of class C GPCRs. Here we characterize the chemical space of bitter and sweet molecules: the majority of bitter compounds show higher hydrophobicity compared to sweet compounds, while sweet molecules have a wider range of sizes. Importantly, recent evidence indicates that TAS1Rs and TAS2Rs are not limited to the oral cavity; moreover, some bitterants are pharmacologically promiscuous, with the hERG potassium channel, cytochrome P450 enzymes, and carbonic anhydrases as common off-targets. Further focus on polypharmacology may unravel new physiological roles for tastant molecules.
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Affiliation(s)
- Antonella Di Pizio
- The Institute of Biochemistry, Food and Nutrition, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University, 76100, Rehovot, Israel; The Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, 91904, Israel
| | - Yaron Ben Shoshan-Galeczki
- The Institute of Biochemistry, Food and Nutrition, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University, 76100, Rehovot, Israel; The Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, 91904, Israel
| | - John E Hayes
- Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, University Park PA, USA
| | - Masha Y Niv
- The Institute of Biochemistry, Food and Nutrition, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University, 76100, Rehovot, Israel; The Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, 91904, Israel.
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48
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Dhillon J, Lee JY, Mattes RD. The cephalic phase insulin response to nutritive and low-calorie sweeteners in solid and beverage form. Physiol Behav 2017; 181:100-109. [PMID: 28899680 PMCID: PMC5634742 DOI: 10.1016/j.physbeh.2017.09.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/08/2017] [Accepted: 09/08/2017] [Indexed: 12/22/2022]
Abstract
The purpose of the study was to examine the role of the cephalic phase insulin response (CPIR) following exposure to nutritive and low-calorie sweeteners in solid and beverage form in overweight and obese adults. In addition, the role of learning on the CPIR to nutritive and low-calorie sweetener exposure was tested. Sixty-four overweight and obese adults (age: 18-50years, BMI: 24-37kg/m2, body fat percentage>25% for men and >32% for women) were sham-fed (at 2-minute intervals for 14min) a randomly assigned test load comprised of a nutritive (sucrose) or low-calorie sweetener (sucralose) in beverage or solid form in phase 1 of the study. A 2-3ml blood sample was collected before and 2, 6, 10, 14, 61, 91 and 121min after oral exposure for serum insulin and glucose analysis. During phase 2, participants underwent a 2-week training period to facilitate associative learning between the sensory properties of test loads and their post-ingestive effects. In phase 3, participants were retested for their cephalic phase responses as in phase 1. Participants were classified as responders if they demonstrated a positive insulin response (rise of serum insulin above baseline i.e. Δ insulin) 2min post-stimulus in phase 1. Among responders exposed to the same sweetener in Phases 1 and 3, the proportion of participants that displayed a rise of insulin with oral exposure to sucralose was significantly greater when the stimulus was in the solid form compared to the beverage form. Sucralose and sucrose exposure elicited similarly significant increases in serum insulin 2min after exposure and significant decreases after 2min in responders in both food forms. The solid food form elicited greater CPIR over 2, 6 and 10min than the beverage form. There was no effect of learning on insulin responses after training. The results indicate the presence of a significant CPIR in a subset of individuals with overweight or obesity after oral exposure to sucralose, especially when present in solid food form. Future studies must confirm the reliability of this response.
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Affiliation(s)
- Jaapna Dhillon
- Department of Nutrition Science, Purdue University, 226 Stone Hall, 700 W State Street, West Lafayette 47907, IN, USA.
| | - Janice Y Lee
- Department of Nutrition Science, Purdue University, 226 Stone Hall, 700 W State Street, West Lafayette 47907, IN, USA.
| | - Richard D Mattes
- Department of Nutrition Science, Purdue University, 226 Stone Hall, 700 W State Street, West Lafayette 47907, IN, USA.
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49
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Rhys NH, Bruni F, Imberti S, McLain SE, Ricci MA. Glucose and Mannose: A Link between Hydration and Sweetness. J Phys Chem B 2017; 121:7771-7776. [DOI: 10.1021/acs.jpcb.7b03919] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- N. H. Rhys
- Department
of Biochemistry, University of Oxford, South Park Road, Oxford, Oxfordshire OX1 3QU, United Kingdom
| | - F. Bruni
- Dipartimento
di Scienze, Sezione di Nanoscienze, Università degli Studi “Roma Tre”, Via della Vasca Navale 84, 00146 Roma, Italy
| | - S. Imberti
- ISIS
Neutron and Muon source, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - S. E. McLain
- Department
of Biochemistry, University of Oxford, South Park Road, Oxford, Oxfordshire OX1 3QU, United Kingdom
| | - M. A. Ricci
- Dipartimento
di Scienze, Sezione di Nanoscienze, Università degli Studi “Roma Tre”, Via della Vasca Navale 84, 00146 Roma, Italy
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50
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Chan CB, Hashemi Z, Subhan FB. The impact of low and no-caloric sweeteners on glucose absorption, incretin secretion, and glucose tolerance. Appl Physiol Nutr Metab 2017; 42:793-801. [DOI: 10.1139/apnm-2016-0705] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The consumption of non-nutritive, low, or no-calorie sweeteners (LCS) is increasing globally. Previously thought to be physiologically inert, there is a growing body of evidence that LCS not only provide a sweet taste but may also elicit metabolic effects in the gastrointestinal tract. This review provides a brief overview of the chemical and receptor-binding properties and effects on chemosensation of different LCS but focuses on the extent to which LCS stimulates glucose transport, incretin and insulin secretion, and effects on glucose tolerance. Aspartame and sucralose both bind to a similar region of the sweet receptor. For sucralose, the data are contradictory regarding effects on glucose tolerance in humans and may depend on the food or beverage matrix and the duration of administration, as suggested by longer term rodent studies. For aspartame, there are fewer data. On the other hand, acesulfame-potassium (Ace-K) and saccharin have similar binding characteristics to each other but, while Ace-K may increase incretin secretion and glucose responses in humans, there are no data on saccharin except in rats, which show impaired glucose tolerance after chronic administration. Additional research, particularly of the effects of chronic consumption, is needed to provide concrete evidence for beneficial or detrimental effects of LCS on blood glucose regulation in humans.
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Affiliation(s)
- Catherine B. Chan
- Department of Agriculture, Food and Nutritional Sciences, University of Alberta, Edmonton, AB T6G 2P5, Canada
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Diabetes, Obesity and Nutrition Strategic Clinical Network, Alberta Health Services, Calgary, AB T2W 1S7, Canada
| | - Zohre Hashemi
- Department of Agriculture, Food and Nutritional Sciences, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - Fatheema B. Subhan
- Department of Agriculture, Food and Nutritional Sciences, University of Alberta, Edmonton, AB T6G 2P5, Canada
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