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Lu R, Li X, Hu J, Wang Y, Jin L. Expression of a single-chain monellin (MNEI) mutant with enhanced stability in transgenic mice milk. Transgenic Res 2024:10.1007/s11248-024-00389-7. [PMID: 38858256 DOI: 10.1007/s11248-024-00389-7] [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: 03/26/2024] [Accepted: 05/31/2024] [Indexed: 06/12/2024]
Abstract
Monellin is a sweet protein that may be used as a safe and healthy sweetener. However, due to its low stability, the application of monellin is currently very limited. Here, we describe a wild-type, a double-sites mutant (E2N/E23A) and a triple-sites mutant (N14A/E23Q/S76Y) of single-chain monellin (MNEI) expressed in transgenic mice milk. Based on enzyme-linked immunoassay (ELISA), Western blot, and sweetness intensity testing, their sweetness and stability were compared. After boiling for 2 min at different pH conditions (2.5, 5.1, 6.8, and 8.2), N14A/E23Q/S76Y-MNEI showed significantly higher sweetness and stability than the wild-type and E2N/E23A-MNEI. These results suggest that N14A/E23Q/S76Y-MNEI shows remarkable potential as a sweetener in the future.
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Affiliation(s)
- Rui Lu
- Jiangsu Food and Pharmaceutical Science College, Huaian, Jiangsu, China
| | - Xiaoming Li
- Jiangsu Agri-Animal Husbandry Vocational College, Taizhou, Jiangsu, China
| | - Jian Hu
- Jiangsu Food and Pharmaceutical Science College, Huaian, Jiangsu, China
| | - Yancui Wang
- Jiangsu Food and Pharmaceutical Science College, Huaian, Jiangsu, China.
| | - Le Jin
- Jiangsu Food and Pharmaceutical Science College, Huaian, Jiangsu, China.
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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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Yasui N, Nakamura K, Yamashita A. A sweet protein monellin as a non-antibody scaffold for synthetic binding proteins. J Biochem 2021; 169:585-599. [PMID: 33386843 DOI: 10.1093/jb/mvaa147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/07/2020] [Indexed: 11/13/2022] Open
Abstract
Synthetic binding proteins that have the ability to bind with molecules can be generated using various protein domains as non-antibody scaffolds. These designer proteins have been used widely in research studies, as their properties overcome the disadvantages of using antibodies. Here, we describe the first application of a phage display to generate synthetic binding proteins using a sweet protein, monellin, as a non-antibody scaffold. Single-chain monellin (scMonellin), in which two polypeptide chains of natural monellin are connected by a short linker, has two loops on one side of the molecule. We constructed phage display libraries of scMonellin, in which the amino acid sequence of the two loops is diversified. To validate the performance of these libraries, we sorted them against the folding mutant of the green fluorescent protein variant (GFPuv) and yeast small ubiquitin-related modifier. We successfully obtained scMonellin variants exhibiting moderate but significant affinities for these target proteins. Crystal structures of one of the GFPuv-binding variants in complex with GFPuv revealed that the two diversified loops were involved in target recognition. scMonellin, therefore, represents a promising non-antibody scaffold in the design and generation of synthetic binding proteins. We termed the scMonellin-derived synthetic binding proteins 'SWEEPins'.
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Affiliation(s)
- Norihisa Yasui
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Kazuaki Nakamura
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Atsuko Yamashita
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
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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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Tang N, Liu J, Cheng Y. Potential improvement of the thermal stability of sweet-tasting proteins by structural calculations. Food Chem 2020; 345:128750. [PMID: 33302109 DOI: 10.1016/j.foodchem.2020.128750] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 11/05/2020] [Accepted: 11/26/2020] [Indexed: 11/19/2022]
Abstract
The low thermal stability of the sweet-tasting proteins limited their applications in food industry. Improve their thermal stability is the key to developing their applications in food processing. In the present study, saturation mutagenesis was performed on 4 sweet-tasting proteins, brazzein (988 mutations), curculin (2109 mutations), monellin (1824 mutations) and thaumatin (3933 mutations), using structural calculations in order to find more thermal stable mutations. The obtained results indicated that our calculated ΔΔG value (ΔΔG < 0 stabilizing, ΔΔG > 0 destabilizing) was a good predictor for predicting changes in thermal stability caused by mutations. Moreover, mutating the negatively charged residues to the other non-negatively charged amino acids was an efficient way to improve the thermal stability of the investigated sweet-tasting proteins. In addition, some promising mutations sites were identified for improving thermal stability using mutagenesis. This study provides useful information for future protein engineering to improve the thermal stability of the sweet-tasting proteins.
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Affiliation(s)
- Ning Tang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing Key Laboratory of Functional Food from Plant Resources, Beijing 100083, China.
| | - Jiachen Liu
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing Key Laboratory of Functional Food from Plant Resources, Beijing 100083, China
| | - Yongqiang Cheng
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing Key Laboratory of Functional Food from Plant Resources, Beijing 100083, China
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6
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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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