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Xie X, Li C, Ban X, Yang H, Li Z. D-allulose 3-epimerase for low-calorie D-allulose synthesis: microbial production, characterization, and applications. Crit Rev Biotechnol 2024:1-20. [PMID: 38973014 DOI: 10.1080/07388551.2024.2368517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 04/15/2023] [Indexed: 07/09/2024]
Abstract
D-allulose, an epimer of D-fructose at C-3 position, is a low-calorie rare sugar with favorable physiochemical properties and special physiological functions, which displays promising perspectives in the food and pharmaceutical industries. Currently, D-allulose is extremely sparse in nature and is predominantly biosynthesized through the isomerization of D-fructose by D-allulose 3-epimerase (DAEase). In recent years, D-allulose 3-epimerase as the key biocatalyst for D-allulose production has received increasing interest. The current review begins by providing a summary of D-allulose regarding its characteristics and applications, as well as different synthesis pathways dominated by biotransformation. Then, the research advances of D-allulose 3-epimerase are systematically reviewed, focusing on heterologous expression and biochemical characterization, crystal structure and molecular modification, and application in D-allulose production. Concerning the constraint of low yield of DAEase for industrial application, this review addresses the various attempts made to promote the production of DAEase in different expression systems. Also, various strategies have been adopted to improve its thermotolerance and catalytic activity, which is mainly based on the structure-function relationship of DAEase. The application of DAEase in D-allulose biosynthesis from D-fructose or low-cost feedstocks through single- or multi-enzymatic cascade reaction has been discussed. Finally, the prospects for related research of D-allulose 3-epimerase are also proposed, facilitating the industrialization of DAEase and more efficient and economical bioproduction of D-allulose.
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Affiliation(s)
- Xiaofang Xie
- Department of Food Science and Technology, National University of Singapore, Singapore, Singapore
- National University of Singapore (Suzhou) Research Institute, Suzhou, Jiangsu, P. R. China
| | - Caiming Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi, P. R. China
| | - Xiaofeng Ban
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi, P. R. China
| | - Hongshun Yang
- Department of Food Science and Technology, National University of Singapore, Singapore, Singapore
- National University of Singapore (Suzhou) Research Institute, Suzhou, Jiangsu, P. R. China
| | - Zhaofeng Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi, P. R. China
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Hu M, Li M, Jiang B, Zhang T. Bioproduction of D-allulose: Properties, applications, purification, and future perspectives. Compr Rev Food Sci Food Saf 2021; 20:6012-6026. [PMID: 34668314 DOI: 10.1111/1541-4337.12859] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 09/07/2021] [Accepted: 09/17/2021] [Indexed: 11/29/2022]
Abstract
D-allulose is the C-3 epimer of D-fructose, which rarely exists in nature, and can be biosynthesized from D-fructose by the catalysis of D-psicose 3-epimerase. D-allulose is safe for human consumption and was recently approved by the United States Food and Drug Administration for food applications. It is not only able be used in food and dietary supplements as a low-calorie sweetener, but also modulates a variety of physiological functions. D-allulose has gained increasing attention owing to its excellent properties. This article presents a review of recent progress on the properties, applications, and bioproduction progress of D-allulose.
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Affiliation(s)
- Mengying Hu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Mengli Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Bo Jiang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Tao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu, 214122, China
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Xia Y, Cheng Q, Mu W, Hu X, Sun Z, Qiu Y, Liu X, Wang Z. Research Advances of d-allulose: An Overview of Physiological Functions, Enzymatic Biotransformation Technologies, and Production Processes. Foods 2021; 10:2186. [PMID: 34574296 PMCID: PMC8467252 DOI: 10.3390/foods10092186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/08/2021] [Accepted: 09/12/2021] [Indexed: 02/02/2023] Open
Abstract
d-allulose has a significant application value as a sugar substitute, not only as a food ingredient and dietary supplement, but also with various physiological functions, such as improving insulin resistance, anti-obesity, and regulating glucolipid metabolism. Over the decades, the physiological functions of d-allulose and the corresponding mechanisms have been studied deeply, and this product has been applied to various foods to enhance food quality and prolong shelf life. In recent years, biotransformation technologies for the production of d-allulose using enzymatic approaches have gained more attention. However, there are few comprehensive reviews on this topic. This review focuses on the recent research advances of d-allulose, including (1) the physiological functions of d-allulose; (2) the major enzyme families used for the biotransformation of d-allulose and their microbial origins; (3) phylogenetic and structural characterization of d-allulose 3-epimerases, and the directed evolution methods for the enzymes; (4) heterologous expression of d-allulose ketose 3-epimerases and biotransformation techniques for d-allulose; and (5) production processes for biotransformation of d-allulose based on the characterized enzymes. Furthermore, the future trends on biosynthesis and applications of d-allulose in food and health industries are discussed and evaluated in this review.
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Affiliation(s)
- Yu Xia
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; (W.M.); (Z.W.)
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; (Q.C.); (Z.S.); (Y.Q.); (X.L.)
- Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi 214122, China
| | - Qianqian Cheng
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; (Q.C.); (Z.S.); (Y.Q.); (X.L.)
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; (W.M.); (Z.W.)
| | - Xiuyu Hu
- China Biotech Fermentation Industry Association, Beijing 100833, China;
| | - Zhen Sun
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; (Q.C.); (Z.S.); (Y.Q.); (X.L.)
| | - Yangyu Qiu
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; (Q.C.); (Z.S.); (Y.Q.); (X.L.)
| | - Ximing Liu
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; (Q.C.); (Z.S.); (Y.Q.); (X.L.)
| | - Zhouping Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; (W.M.); (Z.W.)
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; (Q.C.); (Z.S.); (Y.Q.); (X.L.)
- Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi 214122, China
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Identification of a Novel Cobamide Remodeling Enzyme in the Beneficial Human Gut Bacterium Akkermansia muciniphila. mBio 2020; 11:mBio.02507-20. [PMID: 33293380 PMCID: PMC7733943 DOI: 10.1128/mbio.02507-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cobamides, comprising the vitamin B12 family of cobalt-containing cofactors, are required for metabolism in all domains of life, including most bacteria. Cobamides have structural variability in the lower ligand, and selectivity for particular cobamides has been observed in most organisms studied to date. The beneficial human gut bacterium Akkermansia muciniphila provides metabolites to other members of the gut microbiota by breaking down host mucin, but most of its other metabolic functions have not been investigated. A. muciniphila strain MucT is known to use cobamides, the vitamin B12 family of cofactors with structural diversity in the lower ligand. However, A. muciniphila MucT is unable to synthesize cobamides de novo, and the specific forms that can be used by A. muciniphila have not been examined. We found that the levels of growth of A. muciniphila MucT were nearly identical with each of seven cobamides tested, in contrast to nearly all bacteria that had been studied previously. Unexpectedly, this promiscuity is due to cobamide remodeling—the removal and replacement of the lower ligand—despite the absence of the canonical remodeling enzyme CbiZ in A. muciniphila. We identified a novel enzyme, CbiR, that is capable of initiating the remodeling process by hydrolyzing the phosphoribosyl bond in the nucleotide loop of cobamides. CbiR does not share similarity with other cobamide remodeling enzymes or B12-binding domains and is instead a member of the apurinic/apyrimidinic (AP) endonuclease 2 enzyme superfamily. We speculate that CbiR enables bacteria to repurpose cobamides that they cannot otherwise use in order to grow under cobamide-requiring conditions; this function was confirmed by heterologous expression of cbiR in Escherichia coli. Homologs of CbiR are found in over 200 microbial taxa across 22 phyla, suggesting that many bacteria may use CbiR to gain access to the diverse cobamides present in their environment.
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Mabanglo MF, Huddleston JP, Mukherjee K, Taylor ZW, Raushel FM. Structure and Reaction Mechanism of YcjR, an Epimerase That Facilitates the Interconversion of d-Gulosides to d-Glucosides in Escherichia coli. Biochemistry 2020; 59:2069-2077. [PMID: 32437133 PMCID: PMC7509853 DOI: 10.1021/acs.biochem.0c00334] [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: 11/29/2022]
Abstract
YcjR from Escherichia coli K-12 MG1655 catalyzes the manganese-dependent reversible epimerization of 3-keto-α-d-gulosides to the corresponding 3-keto-α-d-glucosides as a part of a proposed catabolic pathway for the transformation of d-gulosides to d-glucosides. The three-dimensional structure of the manganese-bound enzyme was determined by X-ray crystallography. The divalent manganese ion is coordinated to the enzyme by ligation to Glu-146, Asp-179, His-205, and Glu-240. When either of the two active site glutamate residues is mutated to glutamine, the enzyme loses all catalytic activity for the epimerization of α-methyl-3-keto-d-glucoside at C4. However, the E240Q mutant can catalyze hydrogen-deuterium exchange of the proton at C4 of α-methyl-3-keto-d-glucoside in solvent D2O. The E146Q mutant does not catalyze this exchange reaction. These results indicate that YcjR catalyzes the isomerization of 3-keto-d-glucosides via proton abstraction at C4 by Glu-146 to form a cis-enediolate intermediate that is subsequently protonated on the opposite face by Glu-240 to generate the corresponding 3-keto-d-guloside. This conclusion is supported by docking of the cis-enediolate intermediate into the active site of YcjR based on the known binding orientation of d-fructose and d-psicose in the active site of d-psicose-3-epimerase.
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Affiliation(s)
- Mark F. Mabanglo
- Department of Chemistry, Texas A&M University, College Station, Texas, 77843, USA
| | | | - Keya Mukherjee
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas, 77843, USA
| | - Zane W. Taylor
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas, 77843, USA
| | - Frank M. Raushel
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas, 77843, USA
- Department of Chemistry, Texas A&M University, College Station, Texas, 77843, USA
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Jiang S, Xiao W, Zhu X, Yang P, Zheng Z, Lu S, Jiang S, Zhang G, Liu J. Review on D-Allulose: In vivo Metabolism, Catalytic Mechanism, Engineering Strain Construction, Bio-Production Technology. Front Bioeng Biotechnol 2020; 8:26. [PMID: 32117915 PMCID: PMC7008614 DOI: 10.3389/fbioe.2020.00026] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/13/2020] [Indexed: 01/23/2023] Open
Abstract
Rare sugar D-allulose as a substitute sweetener is produced through the isomerization of D-fructose by D-tagatose 3-epimerases (DTEases) or D-allulose 3-epimerases (DAEases). D-Allulose is a kind of low energy monosaccharide sugar naturally existing in some fruits in very small quantities. D-Allulose not only possesses high value as a food ingredient and dietary supplement, but also exhibits a variety of physiological functions serving as improving insulin resistance, antioxidant enhancement, and hypoglycemic controls, and so forth. Thus, D-allulose has an important development value as an alternative to high-energy sugars. This review provided a systematic analysis of D-allulose characters, application, enzymatic characteristics and molecular modification, engineered strain construction, and processing technologies. The existing problems and its proposed solutions for D-allulose production are also discussed. More importantly, a green and recycling process technology for D-allulose production is proposed for low waste formation, low energy consumption, and high sugar yield.
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Affiliation(s)
- Suwei Jiang
- Department of Biological, Food and Environment Engineering, Hefei University, Hefei, China
- Anhui Key Laboratory of Intensive Processing of Agricultural Products, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Wei Xiao
- Anhui Key Laboratory of Intensive Processing of Agricultural Products, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Xingxing Zhu
- Anhui Key Laboratory of Intensive Processing of Agricultural Products, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Peizhou Yang
- Anhui Key Laboratory of Intensive Processing of Agricultural Products, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Zhi Zheng
- Anhui Key Laboratory of Intensive Processing of Agricultural Products, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Shuhua Lu
- Anhui Key Laboratory of Intensive Processing of Agricultural Products, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Shaotong Jiang
- Anhui Key Laboratory of Intensive Processing of Agricultural Products, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Guochang Zhang
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana–Champaign, Urbana, IL, United States
| | - Jingjing Liu
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana–Champaign, Urbana, IL, United States
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7
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Tseng WC, Chen CN, Hsu CT, Lee HC, Fang HY, Wang MJ, Wu YH, Fang TY. Characterization of a recombinant d-allulose 3-epimerase from Agrobacterium sp. ATCC 31749 and identification of an important interfacial residue. Int J Biol Macromol 2018; 112:767-774. [PMID: 29427680 DOI: 10.1016/j.ijbiomac.2018.02.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 02/05/2018] [Accepted: 02/07/2018] [Indexed: 12/01/2022]
Abstract
d-Allulose 3-epimerase (DAEase) catalyzes the epimerization between d-fructose and d-allulose. We had PCR-cloned and overexpressed the gene encoding Agrobacterium sp. ATCC 31749 DAEase (AsDAEase) in Escherichia coli. A high yield of active AsDAEase, 35,300U/L or 1350U/g of wet cells, was acquired with isopropyl β-d-1-thiogalactopyranoside induction at 20°C for 20h. Although only six residues including residue 234 located in tetrameric interface are different between AsDAEase and A. tumefaciens DAEase (AtDAEase), the specific activity of purified AsDAEase is much larger than that of AtDAEase. The optimal pHs and optimal temperatures of the purified recombinant AsDAEase are 7.5-8.0 and 55-60°C, respectively. The half-life of the enzyme is 267min at 55°C in the presence of 0.1mM Co2+, and the equilibrium ratio between d-allulose and d-fructose is 30:70 at 55°C. Besides characterizing AsDAEase, mutation N234D was constructed to assess its influence on activity. The specific activity of the purified N234D AsDAEase is only 25.5% of wild-type's activity, suggesting residue N234 is an important interfacial residue which substantially affects enzyme activity. The high specific activity and high expression yield of AsDAEase suggest its prospect to be applied in d-allulose production.
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Affiliation(s)
- Wen-Chi Tseng
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan.
| | - Chao-Nan Chen
- Department of Food Science, Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
| | - Chung-Ting Hsu
- Department of Food Science, Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
| | - Hsu-Chieh Lee
- Department of Food Science, Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
| | - Hong-Yi Fang
- Department of Food Science, Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
| | - Ming-Jun Wang
- Department of Food Science, Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
| | - Yi-Hung Wu
- Department of Food Science, Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
| | - Tsuei-Yun Fang
- Department of Food Science, Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
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Zhang W, Yu S, Zhang T, Jiang B, Mu W. Recent advances in d -allulose: Physiological functionalities, applications, and biological production. Trends Food Sci Technol 2016. [DOI: 10.1016/j.tifs.2016.06.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Zhang W, Jia M, Yu S, Zhang T, Zhou L, Jiang B, Mu W. Improving the Thermostability and Catalytic Efficiency of the d-Psicose 3-Epimerase from Clostridium bolteae ATCC BAA-613 Using Site-Directed Mutagenesis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:3386-3393. [PMID: 27082657 DOI: 10.1021/acs.jafc.6b01058] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
d-Psicose is a highly valuable rare sugar because of its excellent physiological properties and commercial potential. d-Psicose 3-epimerase (DPEase) is the key enzyme catalyzing the isomerization of d-fructose to d-psicose. However, the poor thermostability and low catalytic efficiency are serious constraints on industrial application. To address these issues, site-directed mutagenesis of Tyr68 and Gly109 of the Clostridium bolteae DPEase was performed. Compared with the wild-type enzyme, the Y68I variant displayed the highest substrate-binding affinity and catalytic efficiency, and the G109P variant showed the highest thermostability. Furthermore, the double-site Y68I/G109P variant was generated and exhibited excellent enzyme characteristics. The Km value decreased by 17.9%; the kcat/Km increased by 1.2-fold; the t1/2 increased from 156 to 260 min; and the melting temperature (Tm) increased by 2.4 °C. Moreover, Co(2+) enhanced the thermostability significantly, including the t1/2 and Tm values. All of these indicated that the Y68I/G109P variant would be appropriate for the industrial production of d-psicose.
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Affiliation(s)
| | | | | | | | - Leon Zhou
- Roquette America , 1003 Commercial Street, Keokuk, Iowa 52632, United States
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Mu W, Zhang W, Feng Y, Jiang B, Zhou L. Recent advances on applications and biotechnological production of D-psicose. Appl Microbiol Biotechnol 2012; 94:1461-7. [PMID: 22569636 DOI: 10.1007/s00253-012-4093-1] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 01/13/2012] [Accepted: 01/13/2012] [Indexed: 12/01/2022]
Abstract
D-Psicose is a hexoketose monosaccharide sweetener, which is a C-3 epimer of D-fructose and is rarely found in nature. It has 70 % relative sweetness but 0.3 % energy of sucrose, and is suggested as an ideal sucrose substitute for food products. It shows important physiological functions, such as blood glucose suppressive effect, reactive oxygen species scavenging activity, and neuroprotective effect. It also improves the gelling behavior and produces good flavor during food process. This article presents a review of recent studies on the properties, physiological functions, and food application of D-psicose. In addition, the biochemical properties of D-tagatose 3-epimerase family enzymes and the D-psicose-producing enzyme are compared, and the biotechnological production of D-psicose from D-fructose is reviewed.
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Affiliation(s)
- Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
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11
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Chan HC, Zhu Y, Hu Y, Ko TP, Huang CH, Ren F, Chen CC, Ma Y, Guo RT, Sun Y. Crystal structures of D-psicose 3-epimerase from Clostridium cellulolyticum H10 and its complex with ketohexose sugars. Protein Cell 2012; 3:123-31. [PMID: 22426981 PMCID: PMC4875416 DOI: 10.1007/s13238-012-2026-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Accepted: 02/05/2012] [Indexed: 01/07/2023] Open
Abstract
D-psicose 3-epimerase (DPEase) is demonstrated to be useful in the bioproduction of D-psicose, a rare hexose sugar, from D-fructose, found plenty in nature. Clostridium cellulolyticum H10 has recently been identified as a DPEase that can epimerize D-fructose to yield D-psicose with a much higher conversion rate when compared with the conventionally used DTEase. In this study, the crystal structure of the C. cellulolyticum DPEase was determined. The enzyme assembles into a tetramer and each subunit shows a (β/α)(8) TIM barrel fold with a Mn(2+) metal ion in the active site. Additional crystal structures of the enzyme in complex with substrates/products (D-psicose, D-fructose, D-tagatose and D-sorbose) were also determined. From the complex structures of C. cellulolyticum DPEase with D-psicose and D-fructose, the enzyme has much more interactions with D-psicose than D-fructose by forming more hydrogen bonds between the substrate and the active site residues. Accordingly, based on these ketohexose-bound complex structures, a C3-O3 proton-exchange mechanism for the conversion between D-psicose and D-fructose is proposed here. These results provide a clear idea for the deprotonation/protonation roles of E150 and E244 in catalysis.
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Affiliation(s)
- Hsiu-Chien Chan
- Industrial Enzymes National Engineering Laboratory, Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Yueming Zhu
- Industrial Enzymes National Engineering Laboratory, Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Yumei Hu
- Industrial Enzymes National Engineering Laboratory, Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Tzu-Ping Ko
- Institute of Biological Chemistry, Academia Sinica, Taipei, 115 Taiwan, China
| | - Chun-Hsiang Huang
- Industrial Enzymes National Engineering Laboratory, Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Feifei Ren
- Industrial Enzymes National Engineering Laboratory, Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Chun-Chi Chen
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yanhe Ma
- Industrial Enzymes National Engineering Laboratory, Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Rey-Ting Guo
- Industrial Enzymes National Engineering Laboratory, Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Yuanxia Sun
- Industrial Enzymes National Engineering Laboratory, Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
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12
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Yeom SJ, Kim YS, Lim YR, Jeong KW, Lee JY, Kim Y, Oh DK. Molecular characterization of a novel thermostable mannose-6-phosphate isomerase from Thermus thermophilus. Biochimie 2011; 93:1659-67. [PMID: 21729734 DOI: 10.1016/j.biochi.2011.05.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 05/24/2011] [Indexed: 11/25/2022]
Abstract
Mannose-6-phosphate isomerase catalyzes the interconversion of mannose-6-phosphate and fructose-6-phosphate. The gene encoding a putative mannose-6-phosphate isomerase from Thermus thermophilus was cloned and expressed in Escherichia coli. The native enzyme was a 29 kDa monomer with activity maxima for mannose 6-phosphate at pH 7.0 and 80 °C in the presence of 0.5 mM Zn(2+) that was present at one molecule per monomer. The half-lives of the enzyme at 65, 70, 75, 80, and 85 °C were 13, 6.5, 3.7, 1.8, and 0.2 h, respectively. The 15 putative active-site residues within 4.5 Å of the substrate mannose 6-phosphate in the homology model were individually replaced with other amino acids. The sequence alignments, activities, and kinetic analyses of the wild-type and mutant enzymes with amino acid changes at His50, Glu67, His122, and Glu132 as well as homology modeling suggested that these four residues are metal-binding residues and may be indirectly involved in catalysis. In the model, Arg11, Lys37, Gln48, Lys65 and Arg142 were located within 3 Å of the bound mannose 6-phosphate. Alanine substitutions of Gln48 as well as Arg142 resulted in increase of K(m) and dramatic decrease of k(cat), and alanine substitutions of Arg11, Lys37, and Lys65 affected enzyme activity. These results suggest that these 5 residues are substrate-binding residues. Although Trp13 was located more than 3 Å from the substrate and may not interact directly with substrate or metal, the ring of Trp13 was essential for enzyme activity.
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Affiliation(s)
- Soo-Jin Yeom
- Department of Bioscience and Biotechnology, Konkuk University, 1 Hayang-dong, Gangjin-gu, Seoul 143-701, Republic of Korea
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