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Feng Y, Lyu X, Cong Y, Miao T, Fang B, Zhang C, Shen Q, Matthews M, Fisher AJ, Zhang JZH, Zhang L, Yang R. A precise swaying map for how promiscuous cellobiose-2-epimerase operate bi-reaction. Int J Biol Macromol 2023; 253:127093. [PMID: 37758108 DOI: 10.1016/j.ijbiomac.2023.127093] [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: 08/09/2023] [Revised: 09/24/2023] [Accepted: 09/24/2023] [Indexed: 10/02/2023]
Abstract
Promiscuous enzymes play a crucial role in organism survival and new reaction mining. However, comprehensive mapping of the catalytic and regulatory mechanisms hasn't been well studied due to the characteristic complexity. The cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus (CsCE) with complex epimerization and isomerization was chosen to comprehensively investigate the promiscuous mechanisms. Here, the catalytic frame of ring-opening, cis-enediol mediated catalysis and ring-closing was firstly determined. To map the full view of promiscuous CE, the structure of CsCE complex with the isomerized product glucopyranosyl-β1,4-fructose was determined. Combined with computational calculation, the promiscuity was proved a precise cooperation of the double subsites, loop rearrangement, and intermediate swaying. The flexible loop was like a gear, whose structural reshaping regulates the sway of the intermediates between the two subsites of H377-H188 and H377-H247, and thus regulates the catalytic directions. The different protonated states of cis-enediol intermediate catalyzed by H188 were the key point for the catalysis. The promiscuous enzyme tends to utilize all elements at hand to carry out the promiscuous functions.
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Affiliation(s)
- Yinghui Feng
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China; State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 214122 Wuxi, China
| | - Xiaomei Lyu
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 214122 Wuxi, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yalong Cong
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Tingwei Miao
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Bohuan Fang
- Department of Micro/Nano Electronics, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chuanxi Zhang
- Department of Micro/Nano Electronics, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qiang Shen
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Melissa Matthews
- Okinawa Institute of Science and Technology, Onna, Okinawa 904-0495, Japan; Department of Chemistry, University of California Davis, Davis, CA 95616, United States; Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, United States
| | - Andrew J Fisher
- Department of Chemistry, University of California Davis, Davis, CA 95616, United States; Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, United States
| | - John Z H Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China; NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China; Department of Chemistry, New York University, New York, NY 10003, United States
| | - Lujia Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China; NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China.
| | - Ruijin Yang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 214122 Wuxi, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu 214122, China.
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2
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Li Y, Fan Y, Ma X, Wang Y, Liu J. Metagenomic survey reveals global distribution and evolution of microbial sialic acid catabolism. Front Microbiol 2023; 14:1267152. [PMID: 37840734 PMCID: PMC10570557 DOI: 10.3389/fmicb.2023.1267152] [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: 07/26/2023] [Accepted: 09/06/2023] [Indexed: 10/17/2023] Open
Abstract
Sialic acids comprise a varied group of nine-carbon amino sugars found mostly in humans and other higher metazoans, playing major roles in cell interactions with external environments as well as other cells. Microbial sialic acid catabolism (SAC) has long been considered a virulence determinant, and appears to be mainly the purview of pathogenic and commensal bacterial species associated with eukaryotic hosts. Here, we used 2,521 (pre-)assembled metagenomes to evaluate the distribution of SAC in microbial communities from diverse ecosystems and human body parts. Our results demonstrated that microorganisms possessing SAC globally existed in non-host associated environments, although much less frequently than in mammal hosts. We also showed that the ecological significance and taxonomic diversity of microbial SAC have so far been largely underestimated. Phylogenetic analysis revealed a strong signal of horizontal gene transfer among distinct taxa and habitats, and also suggested a specific ecological pressure and a relatively independent evolution history in environmental communities. Our study expanded the known diversity of microbial SAC, and has provided the backbone for further studies on its ecological roles and potential pathogenesis.
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Affiliation(s)
- Yisong Li
- School of Public Health, Qingdao University, Qingdao, China
| | - Yeshun Fan
- School of Public Health, Qingdao University, Qingdao, China
| | - Xiaofang Ma
- Qingdao Municipal Center for Disease Control and Prevention, Qingdao, China
| | - Ying Wang
- School of Public Health, Qingdao University, Qingdao, China
| | - Jie Liu
- School of Public Health, Qingdao University, Qingdao, China
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3
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Zhao M, Zhu Y, Wang H, Zhang W, Mu W. Recent advances on N-acetylneuraminic acid: Physiological roles, applications, and biosynthesis. Synth Syst Biotechnol 2023; 8:509-519. [PMID: 37502821 PMCID: PMC10369400 DOI: 10.1016/j.synbio.2023.06.009] [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: 05/21/2023] [Revised: 06/22/2023] [Accepted: 06/27/2023] [Indexed: 07/29/2023] Open
Abstract
N-Acetylneuraminic acid (Neu5Ac), the most common type of Sia, generally acts as the terminal sugar in cell surface glycans, glycoconjugates, oligosaccharides, lipo-oligosaccharides, and polysaccharides, thus exerting numerous physiological functions. The extensive applications of Neu5Ac in the food, cosmetic, and pharmaceutical industries make large-scale production of this chemical desirable. Biosynthesis which is associated with important application potential and environmental friendliness has become an indispensable approach for large-scale synthesis of Neu5Ac. In this review, the physiological roles of Neu5Ac was first summarized in detail. Second, the safety evaluation, regulatory status, and applications of Neu5Ac were discussed. Third, enzyme-catalyzed preparation, whole-cell biocatalysis, and microbial de novo synthesis of Neu5Ac were comprehensively reviewed. In addition, we discussed the main challenges of Neu5Ac de novo biosynthesis, such as screening and engineering of key enzymes, identifying exporters of intermediates and Neu5Ac, and balancing cell growth and biosynthesis. The corresponding strategies and systematic strategies were proposed to overcome these challenges and facilitate Neu5Ac industrial-scale production.
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Affiliation(s)
- Mingli Zhao
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, PR China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, PR China
| | - Hao Wang
- Bloomage Biotechnology Corp., Ltd., Jinan, Shandong, 250010, PR China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, PR China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, PR China
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4
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Kim SY, Cho HY, Yoon SI. Unique dimeric structure of the DUF2891 family protein CJ0554 from Campylobacter jejuni. Biochem Biophys Res Commun 2023; 655:11-17. [PMID: 36913761 DOI: 10.1016/j.bbrc.2023.03.010] [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: 02/22/2023] [Accepted: 03/05/2023] [Indexed: 03/08/2023]
Abstract
Campylobacter jejuni is a pathogenic bacterium that causes enteritis and Guillain-Barre syndrome in humans. To identify a protein target for the development of a new therapeutic against C. jejuni infection, each gene product of C. jejuni must be functionally characterized. The cj0554 gene of C. jejuni encodes a DUF2891 family protein with unknown functions. To provide functional insights into CJ0554, we determined and analyzed the crystal structure of the CJ0554 protein. CJ0554 adopts an (α/α)6-barrel structure, which consists of an inner α6 ring and an outer α6 ring. CJ0554 assembles into a dimer in a unique top-to-top orientation that is not observed in its structural homologs, N-acetylglucosamine 2-epimerase superfamily members. Dimer formation was verified by analyzing CJ0554 and its ortholog protein through gel-filtration chromatography. The top of the CJ0554 monomer barrel harbors a cavity, which is connected to that of the second subunit in the dimer structure, generating a larger intersubunit cavity. This elongated cavity accommodates extra nonproteinaceous electron density, presumably as a pseudosubstrate, and is lined with generally catalytically active histidine residues that are invariant in CJ0554 orthologs. Therefore, we propose that the cavity functions as the active site of CJ0554.
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Affiliation(s)
- Seung Yeon Kim
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Hye Yeon Cho
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Sung-Il Yoon
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, 24341, Republic of Korea.
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Zhang X, Wang C, Lv X, Liu L, Li J, Du G, Wang M, Liu Y. Engineering of Synthetic Multiplexed Pathways for High-Level N-Acetylneuraminic Acid Bioproduction. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:14868-14877. [PMID: 34851104 DOI: 10.1021/acs.jafc.1c06017] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
N-Acetylneuraminic acid (NeuAc) is widely used as a supplement to promote brain health and enhance immunity. However, the low efficiency of de novo NeuAc synthesis limits its cost-efficient bioproduction. Herein, a synthetic multiplexed pathway engineering (SMPE) strategy is proposed to improve NeuAc synthesis. First, we compare the key enzyme sources and optimize the expression levels of three NeuAc synthesis pathways in Bacillus subtilis; the AGE, NeuC, and NanE pathways, for which NeuAc production reached 3.94, 5.67, and 0.19 g/L, respectively. Next, these synthesis pathways were combined and modularly optimized via the SMPE strategy, with production reaching 7.87 g/L. Finally, fed-batch fermentation in a 5 L fermenter reached 30.10 g/L NeuAc production, the highest reported production using glucose as the sole carbon source. Using a generally regarded as safe strain as a production host, the developed NeuAc-producing approach should be favorable for efficient bioproduction, without the need for plasmids, antibiotics, or chemical inducers.
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Affiliation(s)
- Xiaolong Zhang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Chenyun Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xueqin Lv
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Long Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jianghua Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Guocheng Du
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Miao Wang
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Yanfeng Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi 214122, China
- Qingdao Special Food Research Institute, Qingdao 266109, China
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6
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Liu Z, Li Y, Wu J, Chen S. A Novel Pseudomonas geniculata AGE Family Epimerase/Isomerase and Its Application in d-Mannose Synthesis. Foods 2020; 9:E1809. [PMID: 33291324 PMCID: PMC7762179 DOI: 10.3390/foods9121809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/03/2020] [Accepted: 12/03/2020] [Indexed: 11/29/2022] Open
Abstract
d-mannose has exhibited excellent physiological properties in the food, pharmaceutical, and feed industries. Therefore, emerging attention has been applied to enzymatic production of d-mannose due to its advantage over chemical synthesis. The gene age of N-acetyl-d-glucosamine 2-epimerase family epimerase/isomerase (AGEase) derived from Pseudomonas geniculata was amplified, and the recombinant P. geniculata AGEase was characterized. The optimal temperature and pH of P. geniculata AGEase were 60 °C and 7.5, respectively. The Km, kcat, and kcat/Km of P. geniculata AGEase for d-mannose were 49.2 ± 8.5 mM, 476.3 ± 4.0 s-1, and 9.7 ± 0.5 s-1·mM-1, respectively. The recombinant P. geniculata AGEase was classified into the YihS enzyme subfamily in the AGE enzyme family by analyzing its substrate specificity and active center of the three-dimensional (3D) structure. Further studies on the kinetics of different substrates showed that the P. geniculata AGEase belongs to the d-mannose isomerase of the YihS enzyme. The P. geniculata AGEase catalyzed the synthesis of d-mannose with d-fructose as a substrate, and the conversion rate was as high as 39.3% with the d-mannose yield of 78.6 g·L-1 under optimal reaction conditions of 200 g·L-1d-fructose and 2.5 U·mL-1P. geniculata AGEase. This novel P. geniculata AGEase has potential applications in the industrial production of d-mannose.
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Affiliation(s)
- Zhanzhi Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; (Z.L.); (Y.L.); (J.W.)
- School of Biotechnology and Key Laboratory of Industrial Biotechnology Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China
| | - Ying Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; (Z.L.); (Y.L.); (J.W.)
- School of Biotechnology and Key Laboratory of Industrial Biotechnology Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China
| | - Jing Wu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; (Z.L.); (Y.L.); (J.W.)
- School of Biotechnology and Key Laboratory of Industrial Biotechnology Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China
| | - Sheng Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; (Z.L.); (Y.L.); (J.W.)
- School of Biotechnology and Key Laboratory of Industrial Biotechnology Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China
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7
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Feng Y, Hua X, Shen Q, Matthews M, Zhang Y, Fisher AJ, Lyu X, Yang R. Insight into the potential factors influencing the catalytic direction in cellobiose 2-epimerase by crystallization and mutagenesis. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2020; 76:1104-1113. [PMID: 33135681 DOI: 10.1107/s205979832001222x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 09/03/2020] [Indexed: 11/10/2022]
Abstract
Cellobiose 2-epimerase (CE) is commonly recognized as an epimerase as most CEs mainly exhibit an epimerization activity towards disaccharides. In recent years, several CEs have been found to possess bifunctional epimerization and isomerization activities. They can convert lactose into lactulose, a high-value disaccharide that is widely used in the food and pharmaceutical industries. However, the factors that determine the catalytic direction in CEs are still not clear. In this study, the crystal structures of three newly discovered CEs, CsCE (a bifunctional CE from Caldicellulosiruptor saccharolyticus), StCE (a bifunctional CE from Spirochaeta thermophila DSM 6578) and BtCE (a monofunctional CE from Bacillus thermoamylovorans B4166), were determined at 1.54, 2.05 and 1.80 Å resolution, respectively, in order to search for structural clues to their monofunctional/bifunctional properties. A comparative analysis of the hydrogen-bond networks in the active pockets of diverse CEs, YihS and mannose isomerase suggested that the histidine corresponding to His188 in CsCE is uniquely required to catalyse isomerization. By alignment of the apo and ligand-bound structures of diverse CEs, it was found that bifunctional CEs tend to have more flexible loops and a larger entrance around the active site, and that the flexible loop 148-181 in CsCE displays obvious conformational changes during ligand binding. It was speculated that the reconstructed molecular interactions of the flexible loop during ligand binding helped to motivate the ligands to stretch in a manner beneficial for isomerization. Further site-directed mutagenesis analysis of the flexible loop in CsCE indicated that the residue composition of the flexible loop did not greatly impact epimerization but affects isomerization. In particular, V177D and I178D mutants showed a 50% and 80% increase in isomerization activity over the wild type. This study provides new information about the structural characteristics involved in the catalytic properties of CEs, which can be used to guide future molecular modifications.
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Affiliation(s)
- Yinghui Feng
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Xiao Hua
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Qiuyun Shen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Melissa Matthews
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA
| | - Yuzhu Zhang
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA 94710, USA
| | - Andrew J Fisher
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA
| | - Xiaomei Lyu
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Ruijin Yang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, People's Republic of China
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8
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Pang Q, Han H, Xu Y, Liu X, Qi Q, Wang Q. Exploring Amino Sugar and Phosphoenolpyruvate Metabolism to Improve Escherichia coli N-Acetylneuraminic Acid Production. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:11758-11764. [PMID: 32960055 DOI: 10.1021/acs.jafc.0c04725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
N-acetyl-d-neuraminic acid (NeuAc) has attracted considerable attention because of its wide-ranging applications. The use of cheap carbon sources such as glucose without the addition of any precursor in microbial NeuAc production has many advantages. In this study, improved NeuAc production was attained through the optimization of amino sugar metabolism pathway kinetics and reservation of a phosphoenolpyruvate (PEP) pool in Escherichia coli. N-acylglucosamine 2-epimerase and N-acetylneuraminate synthase from different sources and their best combinations were used to obtain optimized enzyme kinetics and expression intensity, which resulted in a significant increase in NeuAc production. Next, after a design was engineered for enabling the PEP metabolic pathway to retain the PEP pool, the production of NeuAc reached 16.7 g/L, which is the highest NeuAc production rate that has been reported from using glucose as the sole carbon source.
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Affiliation(s)
- Qingxiao Pang
- State Key Laboratory of Microbial Technology, National Glycoengineering Research Center Shandong University, Jinan 250100, P. R. China
| | - Hao Han
- State Key Laboratory of Microbial Technology, National Glycoengineering Research Center Shandong University, Jinan 250100, P. R. China
| | - Ya Xu
- State Key Laboratory of Microbial Technology, National Glycoengineering Research Center Shandong University, Jinan 250100, P. R. China
| | - Xiaoqin Liu
- State Key Laboratory of Microbial Technology, National Glycoengineering Research Center Shandong University, Jinan 250100, P. R. China
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, National Glycoengineering Research Center Shandong University, Jinan 250100, P. R. China
| | - Qian Wang
- State Key Laboratory of Microbial Technology, National Glycoengineering Research Center Shandong University, Jinan 250100, P. R. China
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9
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Microbial production of sialic acid and sialylated human milk oligosaccharides: Advances and perspectives. Biotechnol Adv 2019; 37:787-800. [DOI: 10.1016/j.biotechadv.2019.04.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 04/13/2019] [Accepted: 04/23/2019] [Indexed: 12/21/2022]
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10
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Saburi W, Sato S, Hashiguchi S, Muto H, Iizuka T, Mori H. Enzymatic characteristics of d-mannose 2-epimerase, a new member of the acylglucosamine 2-epimerase superfamily. Appl Microbiol Biotechnol 2019; 103:6559-6570. [DOI: 10.1007/s00253-019-09944-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/20/2019] [Accepted: 05/25/2019] [Indexed: 11/30/2022]
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11
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Gao X, Zhang F, Wu M, Wu Z, Shang G. Production of N-Acetyl-d-neuraminic Acid by Whole Cells Expressing Bacteroides thetaiotaomicron N-Acetyl-d-glucosamine 2-Epimerase and Escherichia coli N-Acetyl-d-neuraminic Acid Aldolase. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:6285-6291. [PMID: 31117501 DOI: 10.1021/acs.jafc.9b01839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
N-Acetyl-d-neuraminic acid (Neu5Ac) is a potential baby nutrient and the key precursor of antiflu medicine Zanamivir. The Neu5Ac chemoenzymatic synthesis consists of N-acetyl-d-glucosamine epimerase (AGE)-catalyzed epimerization of N-acetyl-d-glucosamine (GlcNAc) to N-acetyl-d-mannosamine (ManNAc) and aldolase-catalyzed condensation between ManNAc and pyruvate. Herein, we cloned and characterized BT0453, a novel AGE, from a human gut symbiont Bacteroides thetaiotaomicron. BT0453 shows the highest soluble fraction among the AGEs tested. With GlcNAc and sodium pyruvate as substrates, Neu5Ac production by coupling whole cells expressing BT0453 and Escherichia coli N-acetyl-d-neuraminic acid aldolase was explored. After 36 h, a 53.6% molar yield, 3.6 g L-1 h-1 productivity and 42.9 mM titer of Neu5Ac were obtained. Furthermore, for the first time, the T7- BT0453-T7- nanA polycistronic unit was integrated into the E. coli genome, generating a chromosome-based biotransformation system. BT0453 protein engineering and metabolic engineering studies hold potential for the industrial production of Neu5Ac.
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Affiliation(s)
- Xinyue Gao
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences , Nanjing Normal University , Nanjing 210023 , China
| | - Feifei Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences , Nanjing Normal University , Nanjing 210023 , China
| | - Meng Wu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences , Nanjing Normal University , Nanjing 210023 , China
| | - Zhixin Wu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences , Nanjing Normal University , Nanjing 210023 , China
| | - Guangdong Shang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences , Nanjing Normal University , Nanjing 210023 , China
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12
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Halsør MJH, Rothweiler U, Altermark B, Raeder ILU. The crystal structure of the N-acetylglucosamine 2-epimerase from Nostoc sp. KVJ10 reveals the true dimer. Acta Crystallogr D Struct Biol 2019; 75:90-100. [PMID: 30644848 PMCID: PMC6333288 DOI: 10.1107/s2059798318017047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 11/30/2018] [Indexed: 11/12/2022] Open
Abstract
N-Acetylglucosamine 2-epimerases (AGEs) catalyze the interconversion of N-acetylglucosamine and N-acetylmannosamine. They can be used to perform the first step in the synthesis of sialic acid from N-acetylglucosamine, which makes the need for efficient AGEs a priority. This study presents the structure of the AGE from Nostoc sp. KVJ10 collected in northern Norway, referred to as nAGE10. It is the third AGE structure to be published to date, and the first one in space group P42212. The nAGE10 monomer folds as an (α/α)6 barrel in a similar manner to that of the previously published AGEs, but the crystal did not contain the dimers that have previously been reported. The previously proposed `back-to-back' assembly involved the face of the AGE monomer where the barrel helices are connected by small loops. Instead, a `front-to-front' dimer was found in nAGE10 involving the long loops that connect the barrel helices at this end. This assembly is also present in the other AGE structures, but was attributed to crystal packing, even though the `front' interface areas are larger and are more conserved than the `back' interface areas. In addition, the front-to-front association allows a better explanation of the previously reported observations considering surface cysteines. Together, these results indicate that the `front-to-front' dimer is the most probable biological assembly for AGEs.
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Affiliation(s)
- Marie-Josée Haglund Halsør
- The Norwegian Structural Biology Centre (NorStruct), Department of Chemistry, UiT – The Arctic University of Norway, 9037 Tromsø, Norway
| | - Ulli Rothweiler
- The Norwegian Structural Biology Centre (NorStruct), Department of Chemistry, UiT – The Arctic University of Norway, 9037 Tromsø, Norway
| | - Bjørn Altermark
- The Norwegian Structural Biology Centre (NorStruct), Department of Chemistry, UiT – The Arctic University of Norway, 9037 Tromsø, Norway
| | - Inger Lin Uttakleiv Raeder
- The Norwegian Structural Biology Centre (NorStruct), Department of Chemistry, UiT – The Arctic University of Norway, 9037 Tromsø, Norway
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Chen X, Zhou J, Zhang L, Pu Z, Liu L, Shen W, Fan Y. Development of an Escherichia coli-based biocatalytic system for the efficient synthesis of N-acetyl-D-neuraminic acid. Metab Eng 2018; 47:374-382. [DOI: 10.1016/j.ymben.2018.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 04/12/2018] [Accepted: 04/15/2018] [Indexed: 11/29/2022]
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14
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Saburi W, Jaito N, Kato K, Tanaka Y, Yao M, Mori H. Biochemical and structural characterization of Marinomonas mediterranea d -mannose isomerase Marme_2490 phylogenetically distant from known enzymes. Biochimie 2018; 144:63-73. [DOI: 10.1016/j.biochi.2017.10.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 10/21/2017] [Indexed: 12/01/2022]
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15
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Park AR, Kim JS, Jang SW, Park YG, Koo BS, Lee HC. Rational modification of substrate binding site by structure-based engineering of a cellobiose 2-epimerase in Caldicellulosiruptor saccharolyticus. Microb Cell Fact 2017; 16:224. [PMID: 29233137 PMCID: PMC5726027 DOI: 10.1186/s12934-017-0841-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/06/2017] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Lactulose, a synthetic disaccharide, has received increasing interest due to its role as a prebiotic, specifically proliferating Bifidobacilli and Lactobacilli and enhancing absorption of calcium and magnesium. The use of cellobiose 2-epimerase (CE) is considered an interesting alternative for industrial production of lactulose. CE reversibly converts D-glucose residues into D-mannose residues at the reducing end of unmodified β-1,4-linked oligosaccharides, including β-1,4-mannobiose, cellobiose, and lactose. Recently, a few CE 3D structure were reported, revealing mechanistic details. Using this information, we redesigned the substrate binding site of CE to extend its activity from epimerization to isomerization. RESULTS Using superimposition with 3 known CE structure models, we identified 2 residues (Tyr114, Asn184) that appeared to play an important role in binding epilactose. We modified these residues, which interact with C2 of the mannose moiety, to prevent epimerization to epilactose. We found a Y114E mutation led to increased release of a by-product, lactulose, at 65 °C, while its activity was low at 37 °C. Notably, this phenomenon was observed only at high temperature and more reliably when the substrate was increased. Using Y114E, isomerization of lactose to lactulose was investigated under optimized conditions, resulting in 86.9 g/l of lactulose and 4.6 g/l of epilactose for 2 h when 200 g/l of lactose was used. CONCLUSION These results showed that the Y114E mutation increased isomerization of lactose, while decreasing the epimerization of lactose. Thus, a subtle modification of the active site pocket could extend its native activity from epimerization to isomerization without significantly impairing substrate binding. While additional studies are required to scale this to an industrial process, we demonstrated the potential of engineering this enzyme based on structural analysis.
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Affiliation(s)
- Ah-Reum Park
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea
| | - Jin-Sook Kim
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea
| | - Seung-Won Jang
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea
| | - Young-Gyun Park
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea
| | - Bong-Seong Koo
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea
| | - Hyeon-Cheol Lee
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea.
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16
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Zhang Y, Zhang H, Zheng Q. What regulates the catalytic activities in AGE catalysis? An answer from quantum mechanics/molecular mechanics simulations. Phys Chem Chem Phys 2017; 19:31731-31746. [PMID: 29167851 DOI: 10.1039/c7cp07079a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The AGE superfamily (AGEs) is made up of kinds of isomerase which are very important both physiologically and industrially. One of the most intriguing aspects of AGEs has to do with the mechanism that regulates their activities in single conserved active pocket. In order to clarify the relationship among single conserved active pocket and two activities in AGEs, results for the epimerization activity catalyzed by RaCE and the isomerization activity catalyzed by SeYihS were obtained by using QM/MM umbrella sampling simulations and 2D-FES calculations. Our results show that both of them have similar enzyme-substrate combination mode for inner pyranose ring in single conserved active pocket even though they have different substrate specificity. This means that the pathways of ring opening catalyzed by them are similar. However, one non-conserved residue (Leu183 in RaCE, Met175 in SeYihS) in the active site, which has different steric hindrance, causes a small but effective change in the direction of ring opening in stage 1. And then this change will induce a fundamentally different catalytic activity for RaCE and SeYihS in stage 2. Our results give a novel viewpoint about the regulatory mechanism between CE and YihS in AGEs, and may be helpful for further experiments of rational enzyme design based on the (α/α)6-barrel basic scaffold.
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Affiliation(s)
- Yulai Zhang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Jilin University, Changchun 130023, People's Republic of China.
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17
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Yang P, Wang J, Pang Q, Zhang F, Wang J, Wang Q, Qi Q. Pathway optimization and key enzyme evolution of N-acetylneuraminate biosynthesis using an in vivo aptazyme-based biosensor. Metab Eng 2017; 43:21-28. [PMID: 28780284 DOI: 10.1016/j.ymben.2017.08.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 07/18/2017] [Accepted: 08/01/2017] [Indexed: 10/19/2022]
Abstract
N-acetylneuraminate (NeuAc) biosynthesis has drawn much attention owing to its wide applications in many aspects. Previously, we engineered for the first time an artificial NeuAc biosynthetic pathway in Escherichia coli using glucose as sole substrate. However, rigorous requirements for the flux and cofactor balance make subsequent strain improvement rather difficult. In this study, an in vivo NeuAc biosensor was designed and applied for genetic screening the mutant library of NeuAc producer. Its NeuAc responsive manner was demonstrated using sfgfp as a reporter and a Ni2+-based selection system was developed to couple the cell growth with in vivo NeuAc concentration. Employing this selection system, the NeuAc biosynthesis pathway was optimized and the key enzyme NeuAc synthase was evolved, which improved the titer by 34% and 23%, respectively. The final strain produced up to 8.31g/L NeuAc in minimal medium using glucose as sole carbon source. This work demonstrated the effectiveness of NeuAc biosensor in genetic screening and great potential in metabolic engineering of other organisms.
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Affiliation(s)
- Peng Yang
- State Key Laboratory of Microbial Technology, National Glycoengineering Center, Shandong University, Jinan 250100, People's Republic of China
| | - Jing Wang
- State Key Laboratory of Microbial Technology, National Glycoengineering Center, Shandong University, Jinan 250100, People's Republic of China
| | - Qingxiao Pang
- State Key Laboratory of Microbial Technology, National Glycoengineering Center, Shandong University, Jinan 250100, People's Republic of China
| | - Fengyu Zhang
- State Key Laboratory of Microbial Technology, National Glycoengineering Center, Shandong University, Jinan 250100, People's Republic of China
| | - Junshu Wang
- State Key Laboratory of Microbial Technology, National Glycoengineering Center, Shandong University, Jinan 250100, People's Republic of China
| | - Qian Wang
- State Key Laboratory of Microbial Technology, National Glycoengineering Center, Shandong University, Jinan 250100, People's Republic of China.
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, National Glycoengineering Center, Shandong University, Jinan 250100, People's Republic of China.
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18
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N-acetylglucosamine 2-Epimerase from Pedobacter heparinus: First Experimental Evidence of a Deprotonation/Reprotonation Mechanism. Catalysts 2016. [DOI: 10.3390/catal6120212] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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19
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Klermund L, Riederer A, Hunger A, Castiglione K. Protein engineering of a bacterial N-acyl-d-glucosamine 2-epimerase for improved stability under process conditions. Enzyme Microb Technol 2016; 87-88:70-8. [PMID: 27178797 DOI: 10.1016/j.enzmictec.2016.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/07/2016] [Accepted: 04/11/2016] [Indexed: 01/29/2023]
Abstract
Enzymatic cascade reactions, i.e. the combination of several enzyme reactions in one pot without isolation of intermediates, have great potential for the establishment of sustainable chemical processes. However, many cascade reactions suffer from cross-inhibitions and enzyme inactivation by components of the reaction system. This study focuses on the two-step enzymatic synthesis of N-acetylneuraminic acid (Neu5Ac) using an N-acyl-d-glucosamine 2-epimerase from Anabaena variabilis ATCC 29413 (AvaAGE) in combination with an N-acetylneuraminate lyase (NAL) from Escherichia coli. AvaAGE epimerizes N-acetyl-d-glucosamine (GlcNAc) to N-acetyl-d-mannosamine (ManNAc), which then reacts with pyruvate in a NAL-catalyzed aldol condensation to form Neu5Ac. However, AvaAGE is inactivated by high pyruvate concentrations, which are used to push the NAL reaction toward the product side. A biphasic inactivation was observed in the presence of 50-800mM pyruvate resulting in activity losses of the AvaAGE of up to 60% within the first hour. Site-directed mutagenesis revealed that pyruvate modifies one of the four lysine residues in the ATP-binding site of AvaAGE. Because ATP is an allosteric activator of the epimerase and the binding of the nucleotide is crucial for its catalytic properties, saturation mutagenesis at position K160 was performed to identify the most compatible amino acid exchanges. The best variants, K160I, K160N and K160L, showed no inactivation by pyruvate, but significantly impaired kinetic parameters. For example, depending on the mutant, the turnover number kcat was reduced by 51-68% compared with the wild-type enzyme. A mechanistic model of the Neu5Ac synthesis was established, which can be used to select the AvaAGE variant that is most favorable for a given process condition. The results show that mechanistic models can greatly facilitate the choice of the right enzyme for an enzymatic cascade reaction with multiple cross-inhibitions and inactivation phenomena.
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Affiliation(s)
- Ludwig Klermund
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, 85748 Garching, Germany
| | - Amelie Riederer
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, 85748 Garching, Germany
| | - Annique Hunger
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, 85748 Garching, Germany
| | - Kathrin Castiglione
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, 85748 Garching, Germany.
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20
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Saburi W. Functions, structures, and applications of cellobiose 2-epimerase and glycoside hydrolase family 130 mannoside phosphorylases. Biosci Biotechnol Biochem 2016; 80:1294-305. [PMID: 27031293 DOI: 10.1080/09168451.2016.1166934] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Carbohydrate isomerases/epimerases are essential in carbohydrate metabolism, and have great potential in industrial carbohydrate conversion. Cellobiose 2-epimerase (CE) reversibly epimerizes the reducing end d-glucose residue of β-(1→4)-linked disaccharides to d-mannose residue. CE shares catalytic machinery with monosaccharide isomerases and epimerases having an (α/α)6-barrel catalytic domain. Two histidine residues act as general acid and base catalysts in the proton abstraction and addition mechanism. β-Mannoside hydrolase and 4-O-β-d-mannosyl-d-glucose phosphorylase (MGP) were found as neighboring genes of CE, meaning that CE is involved in β-mannan metabolism, where it epimerizes β-d-mannopyranosyl-(1→4)-d-mannose to β-d-mannopyranosyl-(1→4)-d-glucose for further phosphorolysis. MGPs form glycoside hydrolase family 130 (GH130) together with other β-mannoside phosphorylases and hydrolases. Structural analysis of GH130 enzymes revealed an unusual catalytic mechanism involving a proton relay and the molecular basis for substrate and reaction specificities. Epilactose, efficiently produced from lactose using CE, has superior physiological functions as a prebiotic oligosaccharide.
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Affiliation(s)
- Wataru Saburi
- a Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan
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21
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Van Overtveldt S, Verhaeghe T, Joosten HJ, van den Bergh T, Beerens K, Desmet T. A structural classification of carbohydrate epimerases: From mechanistic insights to practical applications. Biotechnol Adv 2015; 33:1814-28. [DOI: 10.1016/j.biotechadv.2015.10.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 10/15/2015] [Accepted: 10/22/2015] [Indexed: 12/26/2022]
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22
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Krewinkel M, Kaiser J, Merz M, Rentschler E, Kuschel B, Hinrichs J, Fischer L. Novel cellobiose 2-epimerases for the production of epilactose from milk ultrafiltrate containing lactose. J Dairy Sci 2015; 98:3665-78. [DOI: 10.3168/jds.2015-9411] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 03/10/2015] [Indexed: 01/22/2023]
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23
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Klermund L, Riederer A, Groher A, Castiglione K. High-level soluble expression of a bacterial N-acyl-d-glucosamine 2-epimerase in recombinant Escherichia coli. Protein Expr Purif 2015; 111:36-41. [PMID: 25804337 DOI: 10.1016/j.pep.2015.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 01/13/2023]
Abstract
N-Acyl-d-glucosamine 2-epimerase (AGE) is an important enzyme for the biocatalytic synthesis of N-acetylneuraminic acid (Neu5Ac). Due to the wide range of biological applications of Neu5Ac and its derivatives, there has been great interest in its large-scale synthesis. Thus, suitable strategies for achieving high-level production of soluble AGE are needed. Several AGEs from various organisms have been recombinantly expressed in Escherichia coli. However, the soluble expression level was consistently low with an excessive formation of inclusion bodies. In this study, the effects of different solubility-enhancement tags, expression temperatures, chaperones and host strains on the soluble expression of the AGE from the freshwater cyanobacterium Anabaena variabilis ATCC 29413 (AvaAGE) were examined. The optimum combination of tag, expression temperature, co-expression of chaperones and host strain (His6-tag, 37°C, GroEL/GroES, E. coli BL21(DE3)) led to a 264-fold improvement of the volumetric epimerase activity, a measure of the soluble expression, compared to the starting conditions (His6-maltose-binding protein-tag, 20°C, without chaperones, E. coli BL21(DE3)). A maximum yield of 22.5mg isolated AvaAGE per liter shake flask culture was obtained.
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Affiliation(s)
- Ludwig Klermund
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, 85748 Garching, Germany.
| | - Amelie Riederer
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, 85748 Garching, Germany.
| | - Anna Groher
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, 85748 Garching, Germany.
| | - Kathrin Castiglione
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, 85748 Garching, Germany.
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24
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Zhang Y, Zheng Q, Zhang J, Zhang H. Insights into the epimerization activities of RaCE and pAGE: the quantum mechanics/molecular mechanics simulations. RSC Adv 2015. [DOI: 10.1039/c5ra14091a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Ruminococcus albus cellobiose 2-epimerase (RaCE) and N-acetyl-d-glucosamine 2-epimerase from porcine kidney (pAGE) belong to the AGE superfamily and have a detectable AGE activity.
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Affiliation(s)
- Yulai Zhang
- State Key Laboratory of Theoretical and Computational Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
| | - Qingchuan Zheng
- State Key Laboratory of Theoretical and Computational Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
| | - Jilong Zhang
- State Key Laboratory of Theoretical and Computational Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
| | - Hongxing Zhang
- State Key Laboratory of Theoretical and Computational Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
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25
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Wasaki J, Taguchi H, Senoura T, Akasaka H, Watanabe J, Kawaguchi K, Komata Y, Hanashiro K, Ito S. Identification and distribution of cellobiose 2-epimerase genes by a PCR-based metagenomic approach. Appl Microbiol Biotechnol 2014; 99:4287-95. [DOI: 10.1007/s00253-014-6265-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 11/15/2014] [Accepted: 11/19/2014] [Indexed: 11/28/2022]
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26
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Polyhydroyxalkanoate synthase fusions as a strategy for oriented enzyme immobilisation. Molecules 2014; 19:8629-43. [PMID: 24962396 PMCID: PMC6271518 DOI: 10.3390/molecules19068629] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 06/19/2014] [Accepted: 06/19/2014] [Indexed: 01/21/2023] Open
Abstract
Polyhydroxyalkanoate (PHA) is a carbon storage polymer produced by certain bacteria in unbalanced nutrient conditions. The PHA forms spherical inclusions surrounded by granule associate proteins including the PHA synthase (PhaC). Recently, the intracellular formation of PHA granules with covalently attached synthase from Ralstonia eutropha has been exploited as a novel strategy for oriented enzyme immobilisation. Fusing the enzyme of interest to PHA synthase results in a bifunctional protein able to produce PHA granules and immobilise the active enzyme of choice to the granule surface. Functionalised PHA granules can be isolated from the bacterial hosts, such as Escherichia coli, and maintain enzymatic activity in a wide variety of assay conditions. This approach to oriented enzyme immobilisation has produced higher enzyme activities and product levels than non-oriented immobilisation techniques such as protein inclusion based particles. Here, enzyme immobilisation via PHA synthase fusion is reviewed in terms of the genetic designs, the choices of enzymes, the control of enzyme orientations, as well as their current and potential applications.
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27
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Fujiwara T, Saburi W, Matsui H, Mori H, Yao M. Structural insights into the epimerization of β-1,4-linked oligosaccharides catalyzed by cellobiose 2-epimerase, the sole enzyme epimerizing non-anomeric hydroxyl groups of unmodified sugars. J Biol Chem 2013; 289:3405-15. [PMID: 24362032 DOI: 10.1074/jbc.m113.531251] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellobiose 2-epimerase (CE) reversibly converts d-glucose residues into d-mannose residues at the reducing end of unmodified β1,4-linked oligosaccharides, including β-1,4-mannobiose, cellobiose, and lactose. CE is responsible for conversion of β1,4-mannobiose to 4-O-β-d-mannosyl-d-glucose in mannan metabolism. However, the detailed catalytic mechanism of CE is unclear due to the lack of structural data in complex with ligands. We determined the crystal structures of halothermophile Rhodothermus marinus CE (RmCE) in complex with substrates/products or intermediate analogs, and its apo form. The structures in complex with the substrates/products indicated that the residues in the β5-β6 loop as well as those in the inner six helices form the catalytic site. Trp-322 and Trp-385 interact with reducing and non-reducing end parts of these ligands, respectively, by stacking interactions. The architecture of the catalytic site also provided insights into the mechanism of reversible epimerization. His-259 abstracts the H2 proton of the d-mannose residue at the reducing end, and consistently forms the cis-enediol intermediate by facilitated depolarization of the 2-OH group mediated by hydrogen bonding interaction with His-200. His-390 subsequently donates the proton to the C2 atom of the intermediate to form a d-glucose residue. The reverse reaction is mediated by these three histidines with the inverse roles of acid/base catalysts. The conformation of cellobiitol demonstrated that the deprotonation/reprotonation step is coupled with rotation of the C2-C3 bond of the open form of the ligand. Moreover, it is postulated that His-390 is closely related to ring opening/closure by transferring a proton between the O5 and O1 atoms of the ligand.
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Affiliation(s)
- Takaaki Fujiwara
- From the Faculty of Advanced Life Science, Hokkaido University, Kita-10, Nishi-8, Kita-ku, Sapporo 060-0810 and
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28
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Pham TV, Hong SH, Hong MK, Ngo HPT, Oh DK, Kang LW. Expression, crystallization and preliminary X-ray crystallographic analysis of cellobiose 2-epimerase from Dictyoglomus turgidum DSM 6724. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:1163-6. [PMID: 24100573 PMCID: PMC3792681 DOI: 10.1107/s1744309113024391] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 09/02/2013] [Indexed: 11/10/2022]
Abstract
Cellobiose 2-epimerase epimerizes and isomerizes β-1,4- and α-1,4-gluco-oligosaccharides. N-Acyl-D-glucosamine 2-epimerase (DT_epimerase) from Dictyoglomus turgidum has an unusually high catalytic activity towards its substrate cellobiose. DT_epimerase was expressed, purified and crystallized. Crystals were obtained of both His-tagged DT_epimerase and untagged DT_epimerase. The crystals of His-tagged DT_epimerase diffracted to 2.6 Å resolution and belonged to the monoclinic space group P2₁, with unit-cell parameters a=63.9, b=85.1, c=79.8 Å, β=110.8°. With a Matthews coefficient VM of 2.18 Å3 Da(-1), two protomers were expected to be present in the asymmetric unit with a solvent content of 43.74%. The crystals of untagged DT_epimerase diffracted to 1.85 Å resolution and belonged to the orthorhombic space group P2₁2₁2₁, with unit-cell parameters a=55.9, b=80.0, c=93.7 Å. One protomer in the asymmetric unit was expected, with a corresponding VM of 2.26 Å3 Da(-1) and a solvent content of 45.6%.
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Affiliation(s)
- Tan-Viet Pham
- Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Seung-Hye Hong
- Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Myoung-ki Hong
- Department of Biological Sciences, Konkuk University, 1 Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Ho-Phuong-Thuy Ngo
- Department of Biological Sciences, Konkuk University, 1 Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Deok-Kun Oh
- Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Lin-Woo Kang
- Department of Biological Sciences, Konkuk University, 1 Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
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Klermund L, Groher A, Castiglione K. New N-acyl-D-glucosamine 2-epimerases from cyanobacteria with high activity in the absence of ATP and low inhibition by pyruvate. J Biotechnol 2013; 168:256-63. [PMID: 23850800 DOI: 10.1016/j.jbiotec.2013.07.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 06/06/2013] [Accepted: 07/02/2013] [Indexed: 01/17/2023]
Abstract
N-Acetylneuraminic acid, an important component of glycoconjugates with various biological functions, can be produced from N-acetyl-D-glucosamine (GlcNAc) and pyruvate using a one-pot, two-enzyme system consisting of N-acyl-D-glucosamine 2-epimerase (AGE) and N-acetylneuraminate lyase (NAL). In this system, the epimerase catalyzes the conversion of GlcNAc into N-acetyl-D-mannosamine (ManNAc). However, all currently known AGEs have one or more disadvantages, such as a low specific activity, substantial inhibition by pyruvate and strong dependence on allosteric activation by ATP. Therefore, four novel AGEs from the cyanobacteria Acaryochloris marina MBIC 11017, Anabaena variabilis ATCC 29413, Nostoc sp. PCC 7120, and Nostoc punctiforme PCC 73102 were characterized. Among these enzymes, the AGE from the Anabaena strain showed the most beneficial characteristics. It had a high specific activity of 117±2 U mg(-1) at 37 °C (pH 7.5) and an up to 10-fold higher inhibition constant for pyruvate as compared to other AGEs indicating a much weaker inhibitory effect. The investigation of the influence of ATP revealed that the nucleotide has a more pronounced effect on the Km for the substrate than on the enzyme activity. At high substrate concentrations (≥200 mM) and without ATP, the enzyme reached up to 32% of the activity measured with ATP in excess.
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Affiliation(s)
- Ludwig Klermund
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, 85748 Garching, Germany
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Characterization of a recombinant mannobiose 2-epimerase from Spirochaeta thermophila that is suggested to be a cellobiose 2-epimerase. Biotechnol Lett 2013; 35:1873-80. [DOI: 10.1007/s10529-013-1267-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 06/05/2013] [Indexed: 10/26/2022]
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31
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Fujiwara T, Saburi W, Inoue S, Mori H, Matsui H, Tanaka I, Yao M. Crystal structure of Ruminococcus albus cellobiose 2-epimerase: structural insights into epimerization of unmodified sugar. FEBS Lett 2013; 587:840-6. [PMID: 23462136 DOI: 10.1016/j.febslet.2013.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/31/2013] [Accepted: 02/01/2013] [Indexed: 10/27/2022]
Abstract
Enzymatic epimerization is an important modification for carbohydrates to acquire diverse functions attributable to their stereoisomers. Cellobiose 2-epimerase (CE) catalyzes interconversion between d-glucose and d-mannose residues at the reducing end of β-1,4-linked oligosaccharides. Here, we solved the structure of Ruminococcus albus CE (RaCE). The structure of RaCE showed strong similarity to those of N-acetyl-D-glucosamine 2-epimerase and aldose-ketose isomerase YihS with a high degree of conservation of residues around the catalytic center, although sequence identity between them is low. Based on structural comparison, we found that His184 is required for RaCE activity as the third histidine added to two essential histidines in other sugar epimerases/isomerases. This finding was confirmed by mutagenesis, suggesting a new catalytic mechanism for CE involving three histidines.
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Affiliation(s)
- Takaaki Fujiwara
- Graduate School of Life Science, Hokkaido University, Kita-ku, Sapporo, Japan
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Sun W, Ji W, Li N, Tong P, Cheng J, He Y, Chen Y, Chen X, Wu J, Ouyang P, Xie J, Ying H. Construction and expression of a polycistronic plasmid encoding N-acetylglucosamine 2-epimerase and N-acetylneuraminic acid lyase simultaneously for production of N-acetylneuraminic acid. BIORESOURCE TECHNOLOGY 2013; 130:23-9. [PMID: 23280182 DOI: 10.1016/j.biortech.2012.12.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 12/04/2012] [Accepted: 12/07/2012] [Indexed: 05/21/2023]
Abstract
Synthesis of N-acetylneuraminic acid (Neu5Ac) from N-acetylglucosamine (GlcNAc) and pyruvate was carried out by constructing and expressing a polycistronic plasmid encoding an N-acetylglucosamine 2-epimerase (AGE) gene and an N-acetylneuraminic acid lyase (Nal) gene simultaneously. Nal from Escherichia coli K12 and AGEs from Synechocystis sp. PCC 6803 (snAGE) and Anabaena sp. CH1 (anAGE) were used. And four polycistronic plasmids were constructed in which the positions of AGE gene differed with respect to Nal gene. Among these plasmids, pET-28a-Nal-anAGE with anAGE gene located next to Nal gene caused the production of the highest amount of Neu5Ac, generating 61.3g/L in 60h by whole-cell catalysis without the addition of ATP as AGE activator. And pET-28a-Nal-anAGE lowered anAGE's expression level, allowing it to fold properly. Thus, an inclusion-body-free E. coli strain capable of producing Neu5Ac by whole-cell catalysis with high yield and low cost was constructed in the present study.
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Affiliation(s)
- Wujin Sun
- State Key Laboratory of Materials-Oriented Chemical Engineering, National Engineering Technique Research Center for Biotechnology, College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing, China
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33
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Kim JE, Kim YS, Kang LW, Oh DK. Characterization of a recombinant cellobiose 2-epimerase from Dictyoglomus turgidum that epimerizes and isomerizes β-1,4- and α-1,4-gluco-oligosaccharides. Biotechnol Lett 2012; 34:2061-8. [DOI: 10.1007/s10529-012-0999-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 06/22/2012] [Indexed: 11/30/2022]
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34
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N-Acetyl-d-glucosamine 2-epimerase from Anabaena sp. CH1 contains a novel ATP-binding site required for catalytic activity. Process Biochem 2012. [DOI: 10.1016/j.procbio.2012.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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Sola-Carvajal A, Sánchez-Carrón G, García-García MI, García-Carmona F, Sánchez-Ferrer Á. Properties of BoAGE2, a second N-acetyl-D-glucosamine 2-epimerase from Bacteroides ovatus ATCC 8483. Biochimie 2011; 94:222-30. [PMID: 22051376 DOI: 10.1016/j.biochi.2011.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 10/19/2011] [Indexed: 11/15/2022]
Abstract
N-Acyl-D-Glucosamine 2-epimerase (AGE) catalyzes the reversible epimerization between N-acetyl-D-mannosamine (ManNAc) and N-acetyl-D-glucosamine (GlcNAc). Bacteroides ovatus ATCC 8483 shows 3 putative genes for AGE activity (BACOVA_00274, BACOVA_01795 and BACOVA_01816). The BACOVA_00274 gene encodes an AGE (BoAGE1) with strong similarity to the AGE previously characterized in Bacteroides fragilis. Interestingly, the BACOVA_01816 gene (BoAGE2) shares 57% identity with Anabaena sp. CH1 AGE, but has an extra 27-amino acid tag sequence in the N-terminal. When cloned and expressed in Escherichia coli Rosetta (DE3)pLys, BACOVA_01816 was able to convert ManNAc into GlcNAc and vice versa. It was stable over a broad range of pHs and its activity was enhanced by ATP (20 μM). The incubation with ATP stabilized its structure, raising its melting temperature by about 8 °C. In addition, the catalytic efficiency for ManNAc synthesis was higher than that for GlcNAc synthesis. These characteristics make BoAGE2 a promising biocatalyst for sialic acid production using cheap GlcNAc as starting material. BoAGE2 could be considered a Renin-binding Protein and its interaction with renin was studied for the first time in a prokaryotic AGE. Surprisingly, renin activated BoAGE2, an effect which is contrary to that described for mammalian AGE and unrelated with the unique N-terminal tag, since a mutant without this tag was also activated by renin. When BoAGE2 sequence was compared with other related (real and putative) AGE described in the databases, it was seen that AGE enzymes can be divided in 3 different groups. The relationship between these groups is also discussed.
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Affiliation(s)
- Agustín Sola-Carvajal
- Department of Biochemistry and Molecular Biology-A, Faculty of Biology, University of Murcia, Campus Espinardo, E-30100 MURCIA, Spain
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36
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Characterization of a recombinant cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus and its application in the production of mannose from glucose. Appl Microbiol Biotechnol 2011; 92:1187-96. [DOI: 10.1007/s00253-011-3403-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 05/03/2011] [Accepted: 05/19/2011] [Indexed: 10/18/2022]
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37
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Ito S. Catalysis, Structures, and Applications of Carbohydrate Epimerases. J Appl Glycosci (1999) 2010. [DOI: 10.5458/jag.57.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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38
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Ito S. Features and applications of microbial sugar epimerases. Appl Microbiol Biotechnol 2009; 84:1053-60. [PMID: 19697019 DOI: 10.1007/s00253-009-2179-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 07/30/2009] [Accepted: 07/31/2009] [Indexed: 10/20/2022]
Abstract
Sugar (carbohydrate) epimerases catalyze the reversible conversion of a sugar epimer into its counterpart form. More than 20 types of sugar epimerase have been reported to date, and their biological properties, catalytic mechanisms, and 3D structures are very diverse among them. Recently, microbial sugar epimerases have been characterized in detail. This review surveys the catalytic aspects of microbial epimerases, which are relevant for production of bioactive mono- and oligosaccharides.
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Affiliation(s)
- Susumu Ito
- Department of Bioscience and Biotechnology, University of the Ryukyus, Nishihara-cho, Okinawa, Japan.
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39
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Ito S, Hamada S, Ito H, Matsui H, Ozawa T, Taguchi H, Ito S. Site-directed mutagenesis of possible catalytic residues of cellobiose 2-epimerase from Ruminococcus albus. Biotechnol Lett 2009; 31:1065-71. [DOI: 10.1007/s10529-009-9979-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 03/09/2009] [Accepted: 03/09/2009] [Indexed: 11/27/2022]
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40
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Crystal Structure of YihS in Complex with d-Mannose: Structural Annotation of Escherichia coli and Salmonella enterica yihS-encoded Proteins to an Aldose–Ketose Isomerase. J Mol Biol 2008; 377:1443-59. [DOI: 10.1016/j.jmb.2008.01.090] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 01/18/2008] [Accepted: 01/22/2008] [Indexed: 11/20/2022]
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41
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Ito S, Hamada S, Yamaguchi K, Umene S, Ito H, Matsui H, Ozawa T, Taguchi H, Watanabe J, Wasaki J, Ito S. Cloning and sequencing of the cellobiose 2-epimerase gene from an obligatory anaerobe, Ruminococcus albus. Biochem Biophys Res Commun 2007; 360:640-5. [PMID: 17612504 DOI: 10.1016/j.bbrc.2007.06.091] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Accepted: 06/18/2007] [Indexed: 11/22/2022]
Abstract
Cellobiose 2-epimerase (EC 5.1.3.11) was first identified in 1967 as an extracellular enzyme that catalyzes the reversible epimerization between cellobiose and 4-O-beta-D-glucopyranosyl-D-mannose in a culture broth of Ruminococcus albus 7 (ATCC 27210(T)). Here, for the first time, we describe the purification of cellobiose 2-epimerase from R. albus NE1. The enzyme was found to 2-epimerize the reducing terminal glucose moieties of cellotriose and cellotetraose in addition to cellobiose. The gene encoding cellobiose 2-epimerase comprises 1170 bp (389 amino acids) and is present as a single copy in the genome. The deduced amino acid sequence of the mature enzyme contains the possible catalytic residues Arg52, His243, Glu246, and His374. Sequence analysis shows the gene shares a very low level of homology with N-acetyl-D-glucosamine 2-epimerases (EC 5.1.3.8), but no significant homology to any other epimerases reported to date.
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Affiliation(s)
- Shigeaki Ito
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, N-9, W-9, Kita-ku, Sapporo 060-8589, Japan
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42
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Lee YC, Chien HCR, Hsu WH. Production of N-acetyl-D-neuraminic acid by recombinant whole cells expressing Anabaena sp. CH1 N-acetyl-D-glucosamine 2-epimerase and Escherichia coli N-acetyl-D-neuraminic acid lyase. J Biotechnol 2007; 129:453-60. [PMID: 17349707 DOI: 10.1016/j.jbiotec.2007.01.027] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2006] [Revised: 01/17/2007] [Accepted: 01/29/2007] [Indexed: 10/23/2022]
Abstract
N-acetyl-d-neuraminic acid (NeuAc; sialic acid) is a precursor for the manufacture of many pharmaceutical drugs, such as anti-influenza virus agents. To develop a whole cell process for NeuAc production, genes of Anabaena sp. CH1 N-acetyl-d-glucosamine 2-epimerase (bage) and Escherichia coli N-acetyl-d-neuraminic acid lyase (nanA) were cloned and expressed in E. coli BL21 (DE3). The expressed bGlcNAc 2-epimerase was purified from the crude cell extract of IPTG-induced E. coli BL21 (DE3) (pET-bage) to homogeneity by nickel-chelate chromatography. The molecular mass of the purified bGlcNAc 2-epimerase was determined to be 42kDa by SDS-PAGE. The pH and temperature optima of the recombinant bGlcNAc 2-epimerase were pH 7.0 and 50 degrees C, respectively, and only needs 20mum ATP for maximal activity. The specific activity of bGlcNAc 2-epimerase (124Umg(-1) protein) for the conversion of N-acetyl-d-glucosamine to N-acetyl-d-manosamine was about four-fold higher than that of porcine N-acetyl-d-glucosamine 2-epimerase. A stirred glass vessel containing transformed E. coli cells expressing age gene from Anabaena sp. CH1 and NeuAc lyase gene from E. coli NovaBlue separately was used for the conversion of GlcNAc and pyruvate to NeuAc. A maximal productivity of 10.2gNeuAcl(-1)h(-1) with 33.3% conversion yield from GlcNAc could be obtained in a 12-h reaction. The recombinant E. coli cells can be reused for more than eight cycles with a productivity of >8.0gNeuAcL(-1)h(-1). In this process, the expensive activator, ATP, necessary for maximal activity of GlcNAc 2-epimerase in free enzyme system can be omitted.
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Affiliation(s)
- Yen-Chung Lee
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan
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