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Saraiva A, Carrascosa C, Ramos F, Raheem D, Pedreiro S, Vega A, Raposo A. Brazzein and Monellin: Chemical Analysis, Food Industry Applications, Safety and Quality Control, Nutritional Profile and Health Impacts. Foods 2023; 12:foods12101943. [PMID: 37238762 DOI: 10.3390/foods12101943] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/30/2023] [Accepted: 05/06/2023] [Indexed: 05/28/2023] Open
Abstract
Recently, customers have been keener to buy products manufactured using all-natural ingredients with positive health properties, but without losing flavor. In this regard, the objective of the current study is to review the consumption of brazzein and monellin, their nutritional profiles and health effects, and their potential applications in the food industry. This poses challenges with sustainability and important quality and safety indicators, as well as the chemical processes used to determine them. To better understand the utilization of brazzein and monellin, the chemical analysis of these two natural sweet proteins was also reviewed by placing particular emphasis on their extraction methods, purification and structural characterization. Protein engineering is considered a means to improve the thermal stability of brazzein and monellin to enhance their application in food processing, especially where high temperatures are applied. When the quality and safety of these sweet proteins are well-investigated and the approval from safety authorities is secured, the market for brazzein and monellin as food ingredient substitutes for free sugar will be guaranteed in the future. Ultimately, the review on these two natural peptide sweeteners increases the body of knowledge on alleviating problems of obesity, diabetes and other non-communicable diseases.
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Affiliation(s)
- Ariana Saraiva
- Department of Animal Pathology and Production, Bromatology and Food Technology, Faculty of Veterinary, Universidad de Las Palmas de Gran Canaria, Trasmontaña s/n, 35413 Arucas, Spain
| | - Conrado Carrascosa
- Department of Animal Pathology and Production, Bromatology and Food Technology, Faculty of Veterinary, Universidad de Las Palmas de Gran Canaria, Trasmontaña s/n, 35413 Arucas, Spain
| | - Fernando Ramos
- Faculty of Pharmacy, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
- Associated Laboratory for Green Chemistry (LAQV) of the Network of Chemistry and Technology (REQUIMTE), Rua D. Manuel II, Apartado 55142, 4051-401 Porto, Portugal
| | - Dele Raheem
- Arctic Centre, University of Lapland, 96101 Rovaniemi, Finland
| | - Sónia Pedreiro
- Faculty of Pharmacy, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
- Associated Laboratory for Green Chemistry (LAQV) of the Network of Chemistry and Technology (REQUIMTE), Rua D. Manuel II, Apartado 55142, 4051-401 Porto, Portugal
| | - Angelo Vega
- Department of Animal Pathology and Production, Bromatology and Food Technology, Faculty of Veterinary, Universidad de Las Palmas de Gran Canaria, Trasmontaña s/n, 35413 Arucas, Spain
| | - António Raposo
- CBIOS (Research Center for Biosciences and Health Technologies), Universidade Lusófona de Humanidades e Tecnologias, Campo Grande 376, 1749-024 Lisboa, Portugal
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Dupuis JH, Cheung LKY, Newman L, Dee DR, Yada RY. Precision cellular agriculture: The future role of recombinantly expressed protein as food. Compr Rev Food Sci Food Saf 2023; 22:882-912. [PMID: 36546356 DOI: 10.1111/1541-4337.13094] [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: 07/05/2022] [Revised: 11/16/2022] [Accepted: 11/27/2022] [Indexed: 12/24/2022]
Abstract
Cellular agriculture is a rapidly emerging field, within which cultured meat has attracted the majority of media attention in recent years. An equally promising area of cellular agriculture, and one that has produced far more actual food ingredients that have been incorporated into commercially available products, is the use of cellular hosts to produce soluble proteins, herein referred to as precision cellular agriculture (PCAg). In PCAg, specific animal- or plant-sourced proteins are expressed recombinantly in unicellular hosts-the majority of which are yeast-and harvested for food use. The numerous advantages of PCAg over traditional agriculture, including a smaller carbon footprint and more consistent products, have led to extensive research on its utility. This review is the first to survey proteins currently being expressed using PCAg for food purposes. A growing number of viable expression hosts and recent advances for increased protein yields and process optimization have led to its application for producing milk, egg, and muscle proteins; plant hemoglobin; sweet-tasting plant proteins; and ice-binding proteins. Current knowledge gaps present research opportunities for optimizing expression hosts, tailoring posttranslational modifications, and expanding the scope of proteins produced. Considerations for the expansion of PCAg and its implications on food regulation, society, ethics, and the environment are also discussed. Considering the current trajectory of PCAg, food proteins from any biological source can likely be expressed recombinantly and used as purified food ingredients to create novel and tailored food products.
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Affiliation(s)
- John H Dupuis
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lennie K Y Cheung
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lenore Newman
- Food and Agriculture Institute, University of the Fraser Valley, Abbotsford, British Columbia, Canada
| | - Derek R Dee
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Rickey Y Yada
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
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Bilal M, Ji L, Xu S, Zhang Y, Iqbal HMN, Cheng H. Bioprospecting and biotechnological insights into sweet-tasting proteins by microbial hosts-a review. Bioengineered 2022; 13:9815-9828. [PMID: 35435127 PMCID: PMC9161876 DOI: 10.1080/21655979.2022.2061147] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Owing to various undesirable health effects of sugar overconsumption, joint efforts are being made by industrial sectors and regulatory authorities to reduce sugar consumption practices, worldwide. Artificial sweeteners are considered potential substitutes in several products, e.g., sugar alcohols (polyols), high-fructose corn syrup, powdered drink mixes, and other beverages. Nevertheless, their long-standing health effects continue to be debatable. Consequently, growing interest has been shifted in producing non-caloric sweetenersfrom renewable resources to meet consumers' dietary requirements. Except for the lysozyme protein, various sweet proteins including thaumatin, mabinlin, brazzein, monellin, miraculin, pentadin, and curculin have been identified in tropical plants. Given the high cost and challenging extortion of natural resources, producing these sweet proteins using engineered microbial hosts, such as Yarrowia lipolytica, Pichia pastoris, Hansenula polymorpha, Candida boidinii, Arxula adeninivorans, Pichia methanolica, Saccharomyces cerevisiae, and Kluyveromyces lactis represents an appealing choice. Engineering techniques can be applied for large-scale biosynthesis of proteins, which can be used in biopharmaceutical, food, diagnostic, and medicine industries. Nevertheless, extensive work needs to be undertaken to address technical challenges in microbial production of sweet-tasting proteins in bulk. This review spotlights historical aspects, physicochemical properties (taste, safety, stability, solubility, and cost), and recombinant biosynthesis of sweet proteins. Moreover, future opportunities for process improvement based on metabolic engineering strategies are also discussed.
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Affiliation(s)
- Muhammad Bilal
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, China
| | - Liyun Ji
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Shuo Xu
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yue Zhang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Hafiz M. N. Iqbal
- Tecnologico de Monterrey, School of Engineering and Sciences, Monterrey, Mexico
| | - Hairong Cheng
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- CONTACT Hairong Cheng Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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CHOI HE, LEE JI, JO SY, CHAE YC, LEE JH, SUN HJ, KO K, HONG S, KONG KH. Functional expression of the sweet-tasting protein brazzein in transgenic tobacco. FOOD SCIENCE AND TECHNOLOGY 2022. [DOI: 10.1590/fst.40521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Customized yeast cell factories for biopharmaceuticals: from cell engineering to process scale up. Microb Cell Fact 2021; 20:124. [PMID: 34193127 PMCID: PMC8246677 DOI: 10.1186/s12934-021-01617-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/22/2021] [Indexed: 02/06/2023] Open
Abstract
The manufacture of recombinant therapeutics is a fastest-developing section of therapeutic pharmaceuticals and presently plays a significant role in disease management. Yeasts are established eukaryotic host for heterologous protein production and offer distinctive benefits in synthesising pharmaceutical recombinants. Yeasts are proficient of vigorous growth on inexpensive media, easy for gene manipulations, and are capable of adding post translational changes of eukaryotes. Saccharomyces cerevisiae is model yeast that has been applied as a main host for the manufacture of pharmaceuticals and is the major tool box for genetic studies; nevertheless, numerous other yeasts comprising Pichia pastoris, Kluyveromyces lactis, Hansenula polymorpha, and Yarrowia lipolytica have attained huge attention as non-conventional partners intended for the industrial manufacture of heterologous proteins. Here we review the advances in yeast gene manipulation tools and techniques for heterologous pharmaceutical protein synthesis. Application of secretory pathway engineering, glycosylation engineering strategies and fermentation scale-up strategies in customizing yeast cells for the synthesis of therapeutic proteins has been meticulously described.
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Park SW, Kang BH, Lee HM, Lee SJ, Kim HS, Choi HW, Park TJ, Kong KH. Efficient brazzein production in yeast (Kluyveromyces lactis) using a chemically defined medium. Bioprocess Biosyst Eng 2021; 44:913-925. [PMID: 33502625 DOI: 10.1007/s00449-020-02499-y] [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: 09/09/2020] [Accepted: 12/15/2020] [Indexed: 10/22/2022]
Abstract
The sweet-tasting protein brazzein offers considerable potential as a functional sweetener with antioxidant, anti-inflammatory, and anti-allergic properties. Here, we optimized a chemically defined medium to produce secretory recombinant brazzein in Kluyveromyces lactis, with applications in mass production. Compositions of defined media were investigated for two phases of fermentation: the first phase for cell growth, and the second for maximum brazzein secretory production. Secretory brazzein expressed in the optimized defined medium exhibited higher purity than in the complex medium; purification was by ultrafiltration using a molecular weight cutoff, yielding approximately 107 mg L-1. Moreover, the total media cost in this defined medium system was approximately 11% of that in the optimized complex medium to generate equal amounts of brazzein. Therefore, the K. lactis expression system is useful for mass-producing recombinant brazzein with high purity and yield at low production cost and indicates a promising potential for applications in the food industry.
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Affiliation(s)
- Se-Woong Park
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Byung-Ha Kang
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Hyeong-Min Lee
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Sung-Jun Lee
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Han-Seul Kim
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Hye-Won Choi
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Tae Jung Park
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea.
| | - Kwang-Hoon Kong
- Department of Chemistry, College of Natural Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea.
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Kazemi-Nasab A, Shahpiri A. Expression of Brazzein, a Small Sweet-Tasting Protein in Saccharomyces cerevisiae: An Introduction for Production of Sweet Yeasts. Protein Pept Lett 2020; 27:945-952. [PMID: 32228415 DOI: 10.2174/0929866527666200331134431] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/14/2020] [Accepted: 01/20/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND The replacement of carbohydrate sweeteners with protein sweeteners from plants has attracted the interest of researchers because these proteins don't trigger the insulin response and are more nutritive for consumption in food. Brazzein (Braz) is a small and heat- stable sweet protein that has been originally derived from African plant Pentadiplandra brazzeana. In the present work the solubility, sweetness and yield of recombinant forms of Braz in two expression hosts, E. coli and S. cerevisiae were comprised. METHODS The codon-optimized gene of Braz was cloned in expression vectors pET28a and pET41a and GPD. The resulted vectors pET28a-Braz and pEt41a-Braz were transformed into Escherichia coli strain Rosetta (DE3) and the vector GPD-Braz was transformd to S. cerevisiae. The expression of Braz in different systems was analyzed by SDS-PAGE and western blotting. RESULTS The results verified the heterologous expression of Braz in S. cerevisiae carrying GPDBraz. Also the expression of Braz as carboxy-terminal extensions of His-tag and Glutathione-STransferase (GST) were verified in transgenic E. coli containing pET28a-Braz and pET41a-Braz, respectively. CONCLUSION Although the yield of GST-Braz was higher than His-Braz and Braz expressed in S. cerevisiae, but the higher solubility, sweetness, safety (GRAS) are important advantages of the use of S. cerevisiae as expression host for production of Braz. Therefore the result of present work opens new insights for providing the new sweet yeasts that can be used as food additives.
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Affiliation(s)
- Akram Kazemi-Nasab
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran
| | - Azar Shahpiri
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran
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Kim H, Kang J, Hong S, Jo S, Noh H, Kang BH, Park S, Seo YJ, Kong KH, Hong S. 3M-Brazzein as a Natural Sugar Substitute Attenuates Obesity, Metabolic Disorder, and Inflammation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:2183-2192. [PMID: 31984741 DOI: 10.1021/acs.jafc.0c00317] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Obesity is a global chronic disease linked to various diseases. Increased consumption of added sugars, especially in beverages, is a key contributor to the obesity epidemic. It is essential to reduce or replace sugar intake with low-calorie sweeteners. Here, a natural sweet protein, 3M-brazzein, was investigated as a possible sugar substitute. Mice were exposed to 3M-brazzein or 10% sucrose of equivalent sweetness, in drinking water to mimic human obesity development over 15 weeks. Consumption of 3M-brazzein in liquid form did not cause adiposity hypertrophy, resulting in 33.1 ± 0.4 g body weight and 0.90 ± 0.2 mm fat accumulation, which were 35.9 ± 0.7 g (p = 0.0094) and 1.53 ± 0.067 mm (p = 0.0031), respectively, for sucrose supplement. Additionally, 3M-brazzein did not disrupt glucose homeostasis or affect insulin resistance and inflammation. Due to its naturally low-calorie content, 3M-brazzein could also be a potential sugar substitute that reduces adiposity.
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Affiliation(s)
- Hansaem Kim
- Department of Chemistry, College of Natural Sciences , Chung-Ang University , Seoul 06974 , South Korea
| | - Jaeyong Kang
- Department of Chemistry, College of Natural Sciences , Chung-Ang University , Seoul 06974 , South Korea
| | - Seungwoo Hong
- Department of Chemistry, College of Natural Sciences , Chung-Ang University , Seoul 06974 , South Korea
| | - Seonyeong Jo
- Department of Chemistry, College of Natural Sciences , Chung-Ang University , Seoul 06974 , South Korea
| | - Hyangsoon Noh
- Department of Chemistry, College of Natural Sciences , Chung-Ang University , Seoul 06974 , South Korea
| | - Byung-Ha Kang
- Department of Chemistry, College of Natural Sciences , Chung-Ang University , Seoul 06974 , South Korea
| | - Suhyun Park
- School of Electrical and Electronics Engineering , Chung-Ang University , Seoul 06974 , South Korea
| | - Young-Jin Seo
- Department of Life Science, College of Natural Sciences , Chung-Ang University , Seoul 06974 , South Korea
| | - Kwang-Hoon Kong
- Department of Chemistry, College of Natural Sciences , Chung-Ang University , Seoul 06974 , South Korea
| | - Sungguan Hong
- Department of Chemistry, College of Natural Sciences , Chung-Ang University , Seoul 06974 , South Korea
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Thery T, Lynch KM, Arendt EK. Natural Antifungal Peptides/Proteins as Model for Novel Food Preservatives. Compr Rev Food Sci Food Saf 2019; 18:1327-1360. [DOI: 10.1111/1541-4337.12480] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 05/17/2019] [Accepted: 07/04/2019] [Indexed: 01/08/2023]
Affiliation(s)
- Thibaut Thery
- School of Food and Nutritional SciencesUniv. College Cork Ireland
| | - Kieran M. Lynch
- School of Food and Nutritional SciencesUniv. College Cork Ireland
| | - Elke K. Arendt
- School of Food and Nutritional SciencesUniv. College Cork Ireland
- Microbiome IrelandUniv. College Cork Ireland
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Hung CY, Cheng LH, Yeh CM. Functional expression of recombinant sweet-tasting protein brazzein by Escherichia coli and Bacillus licheniformis. FOOD BIOTECHNOL 2019. [DOI: 10.1080/08905436.2019.1618323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Chien-Ya Hung
- Department of Management and Utilization, Fengshan Tropical Horticultural Experiment Branch, Taiwan Agricultural Research Institute, Kaohsiung, Taiwan
| | - Lee-Hao Cheng
- Department of Food Science and Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Chuan-Mei Yeh
- Department of Food Science and Biotechnology, National Chung Hsing University, Taichung, Taiwan
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Lee HM, Park SW, Lee SJ, Kong KH. Optimized production and quantification of the tryptophan-deficient sweet-tasting protein brazzein in Kluyveromyces lactis. Prep Biochem Biotechnol 2019; 49:790-799. [PMID: 31140364 DOI: 10.1080/10826068.2019.1621892] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The sweet-tasting protein brazzein is a candidate sugar substitute owing to its sweet, sugar-like taste and good stability. To commercialize brazzein as a sweetener, optimization of fermentation and purification procedure is necessary. Here, we report the expression conditions of brazzein in the yeast Kluyveromices lactis and purification method for maximum yield. Transformed K. lactis was cultured in YPGlu (pH 7.0) at 25 °C and induced by adding glucose:galactose at a weight ratio of 1:2 (%/%) during the stationary phase, which increased brazzein expression 2.5 fold compared to the previous conditions. Cultures were subjected to heat treatment at 80 °C for 1 h, and brazzein containing supernatant was purified using carboxymethyl-sepharose cation exchange chromatography using 50 mM NaCl in 50 mM sodium acetate buffer (pH 4.0) as a wash buffer and 400 mM NaCl (pH 7.0) for elution. The yield of purified brazzein under these conditions was 2.0-fold higher than that from previous purification methods. We also determined that the NanoOrange assay was a suitable method for quantifying tryptophan-deficient brazzein. Thus, it is possible to obtain pure recombinant brazzein with high yield in K. lactis using our optimized expression, purification, and quantification protocols, which has potential applications in the food industry.
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Affiliation(s)
- Hyung-Min Lee
- a Biomolecular Chemistry Laboratory, Department of Chemistry, College of Natural Sciences, Chung-Ang University , Seoul , Korea
| | - Se-Woong Park
- a Biomolecular Chemistry Laboratory, Department of Chemistry, College of Natural Sciences, Chung-Ang University , Seoul , Korea
| | - Sung-Jun Lee
- a Biomolecular Chemistry Laboratory, Department of Chemistry, College of Natural Sciences, Chung-Ang University , Seoul , Korea
| | - Kwang-Hoon Kong
- a Biomolecular Chemistry Laboratory, Department of Chemistry, College of Natural Sciences, Chung-Ang University , Seoul , Korea
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Chung JH, Kong JN, Choi HE, Kong KH. Antioxidant, anti-inflammatory, and anti-allergic activities of the sweet-tasting protein brazzein. Food Chem 2018; 267:163-169. [DOI: 10.1016/j.foodchem.2017.06.084] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/19/2017] [Accepted: 06/14/2017] [Indexed: 11/30/2022]
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Zhao M, Xu X, Liu B. Structure basis of the improved sweetness and thermostability of a unique double-sites single-chain sweet-tasting protein monellin (MNEI) mutant. Biochimie 2018; 154:156-163. [PMID: 30195051 DOI: 10.1016/j.biochi.2018.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 08/30/2018] [Indexed: 11/27/2022]
Abstract
The sweet protein monellin has an intensely sweet potency but limited stability. We have identified a double-sites mutant (E2N/E23A) of the single-chain monellin (MNEI) with both improved sweetness (about 3-fold) and thermostability (10 °C). However, the structural basis of its superior properties remains elusive until now. Herein we report its crystal structure at a resolution 1.90 Å. Similar to the wild-type, E2N/E23A adopts a wedge-shaped structure consisting of a five-strand β-sheet partially "wrapped" around an α-helix. However, distinguishing parts were present in the loops region, including a remarkable conformation shift from β-strand to loop around residue R39. Molecular docking revealed the persistence of conserved protein-receptor interface and formation of new intermolecular ionic bonds in the E2N/E23A-receptor complex involving the taste-active residue R39 of the sweet protein, which could account for its significant improvement of sweetness. On the other hand, a rearrangement of intramolecular interaction network including the C-H … π bond between A23 and F89 that led to enhanced hydrophobicity in the protein core, could be correlated with its improved thermostability. Furthermore, two new sweeter mutants of MNEI were created. These findings highlight the critical roles of key sweetness determinant residue R39 and hydrophobicity at the protein core for the sweetness and thermostability of the protein, respectively, which thus provide a deeper insight for understanding the structure-function relationship of the sweet protein as well as guidance for rational design of this unique biomacromolecule.
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Affiliation(s)
- Meng Zhao
- School of Food Science & Engineering, Qilu University of Technology (Shandong Academy of Sciences), No. 3501 University Road of Changqing District, 250353, Jinan, Shandong Province, China
| | - Xiangqun Xu
- Shandong Women's University, No. 2399 University Road of Changqing District, 250300, Jinan, Shandong Province, China
| | - Bo Liu
- School of Food Science & Engineering, Qilu University of Technology (Shandong Academy of Sciences), No. 3501 University Road of Changqing District, 250353, Jinan, Shandong Province, China.
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Pluskal T, Weng JK. Natural product modulators of human sensations and mood: molecular mechanisms and therapeutic potential. Chem Soc Rev 2018; 47:1592-1637. [PMID: 28933478 DOI: 10.1039/c7cs00411g] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Humans perceive physical information about the surrounding environment through their senses. This physical information is registered by a collection of highly evolved and finely tuned molecular sensory receptors. A multitude of bioactive, structurally diverse ligands have evolved in nature that bind these molecular receptors. The complex, dynamic interactions between the ligands and the receptors lead to changes in our sensory perception or mood. Here, we review our current knowledge of natural products and their derived analogues that interact specifically with human G protein-coupled receptors, ion channels, and nuclear hormone receptors to modulate the sensations of taste, smell, temperature, pain, and itch, as well as mood and its associated behaviour. We discuss the molecular and structural mechanisms underlying such interactions and highlight cases where subtle differences in natural product chemistry produce drastic changes in functional outcome. We also discuss cases where a single compound triggers complex sensory or behavioural changes in humans through multiple mechanistic targets. Finally, we comment on the therapeutic potential of the reviewed area of research and draw attention to recent technological developments in genomics, metabolomics, and metabolic engineering that allow us to tap the medicinal properties of natural product chemistry without taxing nature.
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Affiliation(s)
- Tomáš Pluskal
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA.
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15
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Abstract
PURPOSE OF REVIEW The current review summarizes and discusses current knowledge on sweeteners and sweetness enhancers. RECENT FINDINGS The perception of sweet taste is mediated by the type 1 taste receptor 2 (T1R2)/type 1 taste receptor 3 (T1R3) receptor, which is expressed in the oral cavity, where it provides input on the caloric and macronutrient contents of ingested food. This receptor recognizes all the compounds (natural or artificial) perceived as sweet by people. Sweeteners are highly chemically diverse including natural sugars, sugar alcohols, natural and synthetic sweeteners, and sweet-tasting proteins. This single receptor is also the target for developing novel sweet enhancers. Importantly, the expression of a functional T1R2/T1R3 receptor is described in numerous extraoral tissues. In this review, the physiological impact of sweeteners is discussed. SUMMARY Sweeteners and sweetness enhancers are perceived through the T1R2/T1R3 taste receptor present both in mouth and numerous extraoral tissues. The accumulated knowledge on sugar substitutes raises the issue of potential health effects.
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Affiliation(s)
- Christine Belloir
- AgroSup Dijon, CNRS, INRA, Université de Bourgogne-Franche Comté, Centre des Sciences du GoÛt et de l'Alimentation, Dijon, France
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