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Baqing L, He X, Ni Q, Zhang H, Li T, Lin X, Guo T, Garba BM, Chen X, Zhang J, Peng C, Wang C, Wu L. Purification of gamma-cyclodextrin via selective coordination with potassium ions to form metal-organic frameworks. Carbohydr Polym 2024; 338:122193. [PMID: 38763708 DOI: 10.1016/j.carbpol.2024.122193] [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: 03/04/2024] [Revised: 04/12/2024] [Accepted: 04/20/2024] [Indexed: 05/21/2024]
Abstract
Efficient purification of gamma-cyclodextrin (γ-CD) is always challenging due to its structural similarity to other CDs and low crystallinity in water. In addressing this issue, an approach was proposed based on the formation mechanism of cyclodextrin metal-organic frameworks (CD-MOFs). This method involved the selective coordination of CDs mixture with potassium ions in water, facilitated by ethanol-induced crystallization, leading to the purification of γ-CD. The results showed that potassium ions enhanced γ-CD crystallization, and ethanol was crucial to selectively coordinating potassium ions with γ-CD. The characterizations revealed that the resulting CD-MOFs exhibited a small particle size, high surface area, and high thermal stability, and was identical to γ-CD-MOF, further indicating the final γ-CD with high purity. The separation factors of γ-CD/α-CD and γ-CD/β-CD were 309 and 260, respectively. Moreover, this method was validated through its application to the industrial enzymatic CDs mixture. The purification of γ-CD could achieve 99.99 ± 0.01 % after four crystallization cycles. Therefore, selectively coordinating with potassium ions to form MOFs provided a valuable reference for the purification of γ-CD and even the direct synthesis of γ-CD-MOF from CDs mixture. This advancement will also benefit the future production and application of γ-CD.
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Affiliation(s)
- Libumo Baqing
- Anhui University of Chinese Medicine, Anhui 230000, China; Yangtze Delta Drug Advanced Research Institute, Jiangsu 226133, China
| | - Xiaojian He
- Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, Nanchang 330004, China; Yangtze Delta Drug Advanced Research Institute, Jiangsu 226133, China
| | - Qijia Ni
- Anhui University of Chinese Medicine, Anhui 230000, China; Yangtze Delta Drug Advanced Research Institute, Jiangsu 226133, China
| | - Hanwen Zhang
- Center for Drug Delivery Systems, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201210, China; Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Tianfu Li
- Yangtze Delta Drug Advanced Research Institute, Jiangsu 226133, China; Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Xueyuan Lin
- Yangtze Delta Drug Advanced Research Institute, Jiangsu 226133, China; Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Tao Guo
- Center for Drug Delivery Systems, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201210, China
| | - Bello Mubarak Garba
- Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, Nanchang 330004, China
| | - Xintao Chen
- Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, Nanchang 330004, China
| | - Jiwen Zhang
- Anhui University of Chinese Medicine, Anhui 230000, China; Center for Drug Delivery Systems, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201210, China; NMPA Key Laboratory for Quality Research and Evaluation of Pharmaceutical Excipients, National Institutes for Food and Drug Control, Beijing 100050, China.
| | - Can Peng
- Anhui University of Chinese Medicine, Anhui 230000, China.
| | - Caifen Wang
- Center for Drug Delivery Systems, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201210, China; Shenyang Pharmaceutical University, Shenyang 110016, China.
| | - Li Wu
- Anhui University of Chinese Medicine, Anhui 230000, China; Center for Drug Delivery Systems, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201210, China; Yangtze Delta Drug Advanced Research Institute, Jiangsu 226133, China; Shenyang Pharmaceutical University, Shenyang 110016, China; NMPA Key Laboratory for Quality Research and Evaluation of Pharmaceutical Excipients, National Institutes for Food and Drug Control, Beijing 100050, China.
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Li X, Jin Z, Bai Y, Svensson B. Progress in cyclodextrins as important molecules regulating catalytic processes of glycoside hydrolases. Biotechnol Adv 2024; 72:108326. [PMID: 38382582 DOI: 10.1016/j.biotechadv.2024.108326] [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: 01/10/2024] [Revised: 02/14/2024] [Accepted: 02/18/2024] [Indexed: 02/23/2024]
Abstract
Cyclodextrins (CDs) are important starch derivatives and commonly comprise α-, β-, and γ-CDs. Their hydrophilic surface and hydrophobic inner cavity enable regulation of enzyme catalysis through direct or indirect interactions. Clarifying interactions between CDs and enzyme is of great value for enzyme screening, mechanism exploration, regulation of catalysis, and applications. We summarize the interactions between CDs and glycoside hydrolases (GHs) according to two aspects: 1) CD as products, substrates, inhibitors and activators of enzymes, directly affecting the reaction process; 2) CDs indirectly affecting the enzymatic reaction by solubilizing substrates, relieving substrate/product inhibition, increasing recombinant enzyme production and storage stability, isolating and purifying enzymes, and serving as ligands in crystal structure to identify functional amino acid residues. Additionally, CD enzyme mimetics are developed and used as catalysts in traditional artificial enzymes as well as nanozymes, making the application of CDs no longer limited to GHs. This review concerns the regulation of GHs catalysis by CDs, and gives insights into research on interactions between enzymes and ligands.
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Affiliation(s)
- Xiaoxiao Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Zhengyu Jin
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yuxiang Bai
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu 214122, China.
| | - Birte Svensson
- Enzyme and Protein Chemistry, Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
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Rabadiya K, Pardhi D, Thaker K, Patoliya J, Rajput K, Joshi R. A review on recent upgradation and strategies to enhance cyclodextrin glucanotransferase properties for its applications. Int J Biol Macromol 2024; 259:129315. [PMID: 38211906 DOI: 10.1016/j.ijbiomac.2024.129315] [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: 06/17/2023] [Revised: 12/27/2023] [Accepted: 01/05/2024] [Indexed: 01/13/2024]
Abstract
Cyclodextrin glycosyltransferase (CGTase) is a significant extracellular enzyme with diverse functions. CGTase is widely used in production of cyclic α-(1,4)-linked oligosaccharides (cyclodextrins) from starch via transglycosylation reaction. Recent discoveries of novel CGTases from different microorganisms have expanded its applications but natural CGTase have lower yield, leading to heterologous expression for increased production to meet various needs. Moreover, significant advancements in directed evolution approach have been explored to alter the molecular structure of CGTase to enhance its performance. This review comprehensively summarizes the strategies employed in heterologous expression to boost CGTase production and secretion in various host. It also outlines molecular engineering approaches aimed to improving CGTase properties, including product and substrate specificity, catalytic efficiency, and thermal stability. Additionally, a considerable stability against changes in temperature and organic solvents can be obtained by immobilization.
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Affiliation(s)
- Khushbu Rabadiya
- Department of Microbiology & Biotechnology, University School of Sciences, Gujarat University, Ahmedabad 380009, Gujarat, India.
| | - Dimple Pardhi
- Department of Microbiology & Biotechnology, University School of Sciences, Gujarat University, Ahmedabad 380009, Gujarat, India.
| | - Khushali Thaker
- Department of Biochemistry & Forensic Science, University School of Sciences, Gujarat University, Ahmedabad 380009, Gujarat, India.
| | - Jaimini Patoliya
- Department of Biochemistry & Forensic Science, University School of Sciences, Gujarat University, Ahmedabad 380009, Gujarat, India.
| | - Kiransinh Rajput
- Department of Microbiology & Biotechnology, University School of Sciences, Gujarat University, Ahmedabad 380009, Gujarat, India.
| | - Rushikesh Joshi
- Department of Biochemistry & Forensic Science, University School of Sciences, Gujarat University, Ahmedabad 380009, Gujarat, India.
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Kortam YG, Abd El-Rahim WM, Khattab AENA, Rebouh NY, Gurina RR, Barakat OS, Zakaria M, Moawad H. Enhancing the Antibiotic Production by Thermophilic Bacteria Isolated from Hot Spring Waters via Ethyl Methanesulfonate Mutagenesis. Antibiotics (Basel) 2023; 12:1095. [PMID: 37508191 PMCID: PMC10376502 DOI: 10.3390/antibiotics12071095] [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: 04/14/2023] [Revised: 06/18/2023] [Accepted: 06/19/2023] [Indexed: 07/30/2023] Open
Abstract
Antibiotic-resistant bacteria represent a serious public health threat. For that reason, the development of new and effective antibiotics to control pathogens has become necessary. The current study aims to search for new microorganisms expressing antibiotic production capacity. Fifteen sites covering a wide range of harsh environmental conditions in Egypt were investigated. Two hundred and eighty bacterial isolates were obtained and then tested against pathogenic bacteria using the agar disk diffusion technique. Fifty-two (18.6% of the total) of the isolates exhibited antagonistic properties, which affected one or more of the tested pathogens. The isolate 113 was identified as Bacillus licheniformis and isolate 10 was identified as Brevibacillus borstelensis using the 16S rRNA technique. The B. licheniformis strain was stronger in antibiotic production against S. typhi, M. luteus, and P. ariginosa, whereas the strain Br. borstelensis was more efficient against B. cereus, E. coli, and Klebs. sp. The sensitivity of the strains to commercial antibiotics showed that B. licheniformis was highly sensitive to seven commercial antibiotics, whereas Br. borstelensis was sensitive to nine antibiotics. The two strains were subjected to ethyl methanesulfonate (EMS) mutagenesis to obtain mutants with a higher antibiotic production. The total bacterial count was measured after treatment with EMS mutagen and showed a significant gradual increase in the antimicrobial activity, which was achieved via shaking in the presence of EMS for 60 min. High antimicrobial activities were noted with 17 and 14 mutants from the B. licheniformis and Br. borstelensis strains, respectively. The mutant B. licheniformis (M15/Amo) was more active than the parent strain against S. aureus (212.5%), while the mutant Br. borstelensis (B7/Neo) was more effective against S. typhi (83.3%). The present study demonstrates the possibility of obtaining potent antibiotic-producing bacteria in hot spring waters and further improving the indigenous bacterial capacity to produce antibiotics by using EMS mutagenesis.
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Affiliation(s)
- Yasmin G Kortam
- Department of Agricultural Microbiology, National Research Centre, Giza 12622, Egypt
| | - Wafaa M Abd El-Rahim
- Department of Agricultural Microbiology, National Research Centre, Giza 12622, Egypt
| | | | - Nazih Y Rebouh
- Department of Environmental Management, Institute of Environmental Engineering, RUDN University, 6 Miklukho-Maklaya Street, 117198 Moscow, Russia
| | - Regina R Gurina
- Technosphere Security Department, RUDN University, 6 Miklukho-Maklaya Street, 117198 Moscow, Russia
| | - Olfat S Barakat
- Department of Agricultural Microbiology, Faculty of Agriculture, Cairo University, Cairo 12613, Egypt
| | - Mohamed Zakaria
- Department of Agricultural Microbiology, Faculty of Agriculture, Cairo University, Cairo 12613, Egypt
| | - Hassan Moawad
- Department of Agricultural Microbiology, National Research Centre, Giza 12622, Egypt
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Zhang R, Tang R, Wang W, Bi J, Xu X, Fan Q, Li Y, Chen Q. Engineering of cyclodextrin glycosyltransferase improves the conversion efficiency of rebaudioside A to glucosylated steviol glycosides and increases the content of short-chain glycosylated steviol glycoside. Microb Cell Fact 2023; 22:113. [PMID: 37312096 DOI: 10.1186/s12934-023-02121-2] [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: 03/28/2023] [Accepted: 05/24/2023] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND Compared with steviol glycosides, the taste of glucosylated steviol glycosides is better and more similar to that of sucrose. At present, cyclodextrin glucanotransferase (CGTase) is primarily used to catalyze the conversion of steviol glycosides to glucosylated steviol glycosides, with soluble starch serving as a glycosyl donor. The main disadvantages of enzymatic transglycosylation are the limited number of enzymes available, the low conversion rates that result in low yields, and the lack of selectivity in the degree of glycosylation of the products. In order to fill these gaps, the proteome of Alkalihalobacillus oshimensis (also named Bacillus oshimensis) was used for mining novel CGTases. RESULTS Here, CGTase-15, a novel β-CGTase with a wide pH adaptation range, was identified and characterized. The catalyzed product of CGTase-15 tasted better than that of the commercial enzyme (Toruzyme® 3.0 L). In addition, two amino acid sites, Y199 and G265, which play important roles in the conversion of steviol glycosides to glucosylated steviol glycosides were identified by site-directed mutagenesis. Compared with CGTase-15, CGTase-15-Y199F mutant significantly increased the conversion rate of rebaudioside A (RA) to glucosylated steviol glycosides. Compared with CGTase-15, the content of short-chain glycosylated steviol glycosides catalyzed by CGTase-15-G265A mutant was significantly increased. Moreover, the function of Y199 and G265 was verified in other CGTases. The above mutation pattern has also been applied to CGTase-13 (a CGTase discovered by our laboratory with great potential in the production of glycosylated steviol glycosides), confirming that the catalytic product of CGTase-13-Y189F/G255A mutant has a better taste than that of CGTase-13. CONCLUSIONS This is the first report on the improvement of the sensory profiles of glycosylated steviol glycosides through site-directed mutagenesis of CGTase, which is significant for the production of glycosylated steviol glycosides.
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Affiliation(s)
- Ruiqin Zhang
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Food and Biological Engineering of Zhejiang Province, Research and Development Department, Hangzhou Wahaha Technology Co. Ltd, Hangzhou Wahaha Group Co. Ltd, Hangzhou, 310018, China
| | - Ruiqi Tang
- Key Laboratory of Bioprocess Engineering of Jiangxi Province, College of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, 330013, China
| | - Wei Wang
- School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou, 310000, China
| | - Jiahua Bi
- Key Laboratory of Food and Biological Engineering of Zhejiang Province, Research and Development Department, Hangzhou Wahaha Technology Co. Ltd, Hangzhou Wahaha Group Co. Ltd, Hangzhou, 310018, China
| | - Xianrui Xu
- Key Laboratory of Food and Biological Engineering of Zhejiang Province, Research and Development Department, Hangzhou Wahaha Technology Co. Ltd, Hangzhou Wahaha Group Co. Ltd, Hangzhou, 310018, China
| | - Qiuling Fan
- Key Laboratory of Food and Biological Engineering of Zhejiang Province, Research and Development Department, Hangzhou Wahaha Technology Co. Ltd, Hangzhou Wahaha Group Co. Ltd, Hangzhou, 310018, China
| | - Yanjun Li
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Food and Biological Engineering of Zhejiang Province, Research and Development Department, Hangzhou Wahaha Technology Co. Ltd, Hangzhou Wahaha Group Co. Ltd, Hangzhou, 310018, China
| | - Qihe Chen
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, 310058, China.
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Li X, Zheng D, Wu J, Jin Z, Svensson B, Bai Y. Increasing γ-CD conversion rates by improving thermostability of Bacillus sp. FJAT-44876 γ-CGTase. FOOD BIOSCI 2022. [DOI: 10.1016/j.fbio.2022.102204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Lanthanide (Eu 3+/Tb 3+)-Loaded γ-Cyclodextrin Nano-Aggregates for Smart Sensing of the Anticancer Drug Irinotecan. Int J Mol Sci 2022; 23:ijms23126597. [PMID: 35743042 PMCID: PMC9223530 DOI: 10.3390/ijms23126597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 06/10/2022] [Accepted: 06/11/2022] [Indexed: 01/11/2023] Open
Abstract
The clinical use of anticancer drugs necessitates new technologies for their safe, sensitive, and selective detection. In this article, lanthanide (Eu3+ and Tb3+)-loaded γ-cyclodextrin nano-aggregates (ECA and TCA) are reported, which sensitively detects the anticancer drug irinotecan by fluorescence intensity changes. Fluorescent lanthanide (Eu3+ and Tb3+) complexes exhibit high fluorescence intensity, narrow and distinct emission bands, long fluorescence lifetime, and insensitivity to photobleaching. However, these lanthanide (Eu3+ and Tb3+) complexes are essentially hydrophobic, toxic, and non-biocompatible. Lanthanide (Eu3+ and Tb3+) complexes were loaded into naturally hydrophilic γ-cyclodextrin to form fluorescent nano-aggregates. The biological nontoxicity and cytocompatibility of ECA and TCA fluorescent nanoparticles were demonstrated by cytotoxicity experiments. The ECA and TCA fluorescence nanosensors can detect irinotecan selectively and sensitively through the change of fluorescence intensity, with detection limits of 6.80 μM and 2.89 μM, respectively. ECA can safely detect irinotecan in the cellular environment, while TCA can detect irinotecan intracellularly and is suitable for cell labeling.
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Saini K, Gupta R. Cell Surface Expression of γ-CGTase from Evansella caseinilytica on E. coli: Application in the enzymatic conversion of starch to γ-cyclodextrin. Enzyme Microb Technol 2022; 159:110066. [DOI: 10.1016/j.enzmictec.2022.110066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/11/2022] [Accepted: 05/12/2022] [Indexed: 11/15/2022]
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Wu H, Li X, Ji H, Svensson B, Bai Y. Improved production of gamma-cyclodextrin from high-concentrated starch using enzyme pretreatment under swelling condition. Carbohydr Polym 2022; 284:119124. [DOI: 10.1016/j.carbpol.2022.119124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 01/04/2022] [Accepted: 01/07/2022] [Indexed: 11/02/2022]
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Engineering of cyclodextrin glycosyltransferase from Paenibacillus macerans for enhanced product specificity of long-chain glycosylated sophoricosides. MOLECULAR CATALYSIS 2022. [DOI: 10.1016/j.mcat.2022.112147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Docking-guided rational engineering of a macrolide glycosyltransferase glycodiversifies epothilone B. Commun Biol 2022; 5:100. [PMID: 35087210 PMCID: PMC8795383 DOI: 10.1038/s42003-022-03047-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 01/06/2022] [Indexed: 11/09/2022] Open
Abstract
Glycosyltransferases typically display acceptor substrate flexibility but more stringent donor specificity. BsGT-1 is a highly effective glycosyltransferase to glycosylate macrolides, including epothilones, promising antitumor compounds. Here, we show that BsGT-1 has three major regions significantly influencing the glycodiversification of epothilone B based on structural molecular docking, "hot spots" alanine scanning, and site saturation mutagenesis. Mutations in the PSPG-like motif region and the C2 loop region are more likely to expand donor preference; mutations of the flexible N3 loop region located at the mouth of the substrate-binding cavity produce novel epothilone oligosaccharides. These "hot spots" also functioned in homologues of BsGT-1. The glycosides showed significantly enhanced water solubility and decreased cytotoxicity, although the glycosyl appendages of epothilone B also reduced drug permeability and attenuated antitumor efficacy. This study laid a foundation for the rational engineering of other GTs to synthesize valuable small molecules.
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Saini K, Kashyap A, Saini M, Gupta R. Gamma cyclodextrin glycosyltransferase from evansella caseinilytica: production, characterization and product specificity. 3 Biotech 2022; 12:16. [PMID: 34926120 PMCID: PMC8669088 DOI: 10.1007/s13205-021-03077-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 11/26/2021] [Indexed: 02/07/2023] Open
Abstract
Alkalohalophilic Evansella caseinilytica produced an extracellular cyclodextrin glycosyltransferase (CGTase) with cyclization activity of 43.5 ± 4.4 U/L in M1 medium containing 1% starch and 6% NaCl in nutrient broth at 37 ºC, pH 9.0, after 48 h. This is the first report of CGTase from this bacterium. 0.1% starch was found to induce CGTase, and further optimization using one variable at a time approach followed by statistical optimization led to 5.5-fold enhancement resulting in 240.5 ± 5.46 U/L. Six parameters were identified as positive signals using Plackett-Burman (PB). Of these, yeast extract, MgSO4 and tryptone were taken further for Response Surface Methodology (RSM) by disposing beef extract and fixing starch and soya peptone. The optimized M4 medium consisted of tryptone (0.1%, w/v), yeast extract (0.25%, w/v), MgSO4 (8 mM, w/v), potato starch (0.1%, w/v) and soya peptone (0.2%, w/v). CGTase was further purified with 6.44-fold purification and 19.32% yield employing starch affinity. It was found to be monomeric, corresponding to a size of 68 kDa as estimated by SDS-PAGE and was further confirmed to be 65 kDa by size exclusion chromatography. γ-Cyclodextrins were produced as the major product with a conversion of 5% soluble starch into 20.38% γ-cyclodextrins after 24 h reaction, as determined by HPLC. Peptide fingerprint after LC-MS analysis matched with IPT/TIG domain-containing protein within the genome of E. caseinilytica. Further blastp analysis revealed the closest homology with γ-CGTase from an alkalophilic E. clarkii, thereby confirming CGTase from E. caseinilytica as γ-CGTase.
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Affiliation(s)
- Kuldeep Saini
- Department of Microbiology, University of Delhi South Campus, New Delhi, 110021 India
| | - Amuliya Kashyap
- Department of Microbiology, University of Delhi South Campus, New Delhi, 110021 India
| | - Meenu Saini
- Department of Microbiology, University of Delhi South Campus, New Delhi, 110021 India
| | - Rani Gupta
- Department of Microbiology, University of Delhi South Campus, New Delhi, 110021 India
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