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Feng X, Hong S, Zhao H, Vuong TV, Master ER. Biocatalytic cascade to polysaccharide amination. Biotechnol Biofuels Bioprod 2024; 17:34. [PMID: 38409122 PMCID: PMC10898118 DOI: 10.1186/s13068-024-02477-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 02/15/2024] [Indexed: 02/28/2024]
Abstract
BACKGROUND Chitin, the main form of aminated polysaccharide in nature, is a biocompatible, polycationic, and antimicrobial biopolymer used extensively in industrial processes. Despite the abundance of chitin, applications thereof are hampered by difficulties in feedstock harvesting and limited structural versatility. To address these problems, we proposed a two-step cascade employing carbohydrate oxidoreductases and amine transaminases for plant polysaccharide aminations via one-pot reactions. Using a galactose oxidase from Fusarium graminearum for oxidation, this study compared the performance of CvATA (from Chromobacterium violaceum) and SpATA (from Silicibacter pomeroyi) on a range of oxidized carbohydrates with various structures and sizes. Using a rational enzyme engineering approach, four point mutations were introduced on the SpATA surface, and their effects on enzyme activity were evaluated. RESULTS Herein, a quantitative colorimetric assay was developed to enable simple and accurate time-course measurement of the yield of transamination reactions. With higher operational stability, SpATA produced higher product yields in 36 h reactions despite its lower initial activity. Successful amination of oxidized galactomannan by SpATA was confirmed using a deuterium labeling method; higher aminated carbohydrate yields achieved with SpATA compared to CvATA were verified using HPLC and XPS. By balancing the oxidase and transaminase loadings, improved operating conditions were identified where the side product formation was largely suppressed without negatively impacting the product yield. SpATA mutants with multiple alanine substitutions besides E407A showed improved product yield. The E407A mutation reduced SpATA activity substantially, supporting its predicted role in maintaining the dimeric enzyme structure. CONCLUSIONS Using oxidase-amine transaminase cascades, the study demonstrated a fully enzymatic route to polysaccharide amination. Although the activity of SpATA may be further improved via enzyme engineering, the low operational stability of characterized amine transaminases, as a result of low retention of PMP cofactors, was identified as a key factor limiting the yield of the designed cascade. To increase the process feasibility, future efforts to engineer improved SpATA variants should focus on improving the cofactor affinity, and thus the operational stability of the enzyme.
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Affiliation(s)
- Xuebin Feng
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Siyi Hong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Hongbo Zhao
- Department of Food and Nutrition, University of Helsinki, Helsinki, Finland
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada.
- Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland.
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Sharan AA, Bellemare A, DiFalco M, Tsang A, Vuong TV, Edwards EA, Master ER. Functional screening pipeline to uncover laccase-like multicopper oxidase enzymes that transform industrial lignins. Bioresour Technol 2024; 393:130084. [PMID: 38000639 DOI: 10.1016/j.biortech.2023.130084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/07/2023] [Accepted: 11/19/2023] [Indexed: 11/26/2023]
Abstract
Laccase-like multicopper oxidases are recognized for their potential to alter the reactivity of lignins for application in value-added products. Typically, model compounds are employed to discover such enzymes; however, they do not represent the complexity of industrial lignin substrates. In this work, a screening pipeline was developed to test enzymes simultaneously on model compounds and industrial lignins. A total of 12 lignin-active fungal multicopper oxidases were discovered, including 9 enzymes active under alkaline conditions (pH 11.0). Principal component analysis revealed the poor ability of model compounds to predict enzyme performance on industrial lignins. Additionally, sequence similarity analyses grouped these enzymes with Auxiliary Activity-1 sub-families with few previously characterized members, underscoring their taxonomic novelty. Correlation between the lignin-activity of these enzymes and their taxonomic origin, however, was not observed. These are critical insights to bridge the gap between enzyme discovery and application for industrial lignin valorization.
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Affiliation(s)
- Anupama A Sharan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
| | - Annie Bellemare
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Canada
| | - Marcos DiFalco
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Canada
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Canada
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
| | - Elizabeth A Edwards
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada; Department of Cell and Systems Biology, University of Toronto, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada; Department of Bioproducts and Biosystems, Aalto University, Finland.
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Ho M, Au A, Flick R, Vuong TV, Sklavounos AA, Swyer I, Yip CM, Wheeler AR. Antifouling Properties of Pluronic and Tetronic Surfactants in Digital Microfluidics. ACS Appl Mater Interfaces 2023; 15:6326-6337. [PMID: 36696478 DOI: 10.1021/acsami.2c17317] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Fouling at liquid-solid interfaces is a pernicious problem for a wide range of applications, including those that are implemented by digital microfluidics (DMF). There are several strategies that have been used to combat surface fouling in DMF, the most common being inclusion of amphiphilic surfactant additives in the droplets to be manipulated. Initial studies relied on Pluronic additives, and more recently, Tetronic additives have been used, which has allowed manipulation of complex samples like serum and whole blood. Here, we report our evaluation of 19 different Pluronic and Tetronic additives, with attempts to determine (1) the difference in antifouling performance between the two families, (2) the structural similarities that predict exceptional antifouling performance, and (3) the mechanism of the antifouling behavior. Our analysis shows that both Pluronic and Tetronic additives with modest molar mass, poly(propylene oxide) (PPO) ≥50 units, poly(ethylene oxide) (PEO) mass percentage ≤50%, and hydrophilic-lipophilic balance (HLB) ca. 13-15 allow for exceptional antifouling performance in DMF. The most promising candidates, P104, P105, and T904, were able to support continuous movement of droplets of serum for more than 2 h, a result (for devices operating in air) previously thought to be out of reach for this technique. Additional results generated using device longevity assays, intrinsic fluorescence measurements, dynamic light scattering, asymmetric flow field flow fractionation, supercritical angle fluorescence microscopy, atomic force microscopy, and quartz crystal microbalance measurements suggest that the best-performing surfactants are more likely to operate by forming a protective layer at the liquid-solid interface than by complexation with proteins. We propose that these results and their implications are an important step forward for the growing community of users of this technique, which may provide guidance in selecting surfactants for manipulating biological matrices for a wide range of applications.
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Affiliation(s)
- Man Ho
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Aaron Au
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
| | - Robert Flick
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Thu V Vuong
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Alexandros A Sklavounos
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Ian Swyer
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Christopher M Yip
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Aaron R Wheeler
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
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Nouri S, Holcroft J, Caruso LL, Vuong TV, Simmons CA, Master ER, Ganss B. An SCPPPQ1/LAM332 protein complex enhances the adhesion and migration of oral epithelial cells: Implications for dentogingival regeneration. Acta Biomater 2022; 147:209-220. [PMID: 35643199 DOI: 10.1016/j.actbio.2022.05.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/16/2022] [Accepted: 05/19/2022] [Indexed: 12/11/2022]
Abstract
Common periodontal disease treatment procedures often fail to restore the structural integrity of the junctional epithelium (JE), the epithelial attachment of the gum to the tooth, leaving the tooth-gum interface prone to bacterial colonization. To address this issue, we introduced a novel bio-inspired protein complex comprised of a proline-rich enamel protein, SCPPPQ1, and laminin 332 (LAM332) to enhance the JE attachment. Using quartz crystal microbalance with dissipation monitoring (QCM-D), we showed that SCPPPQ1 and LAM332 interacted and assembled into a protein complex with high-affinity adsorption of 5.9e-8 [M] for hydroxyapatite (HA), the main component of the mineralized tooth surfaces. We then designed a unique shear device to study the adhesion strength of the oral epithelial cells to HA. The SCPPPQ1/LAM332 complex resulted in a twofold enhancement in adhesion strength of the cells to HA compared to LAM332 (from 31 dyn/cm2 to 63 dyn/cm2). In addition, using a modified wound-healing assay, we showed that gingival epithelial cells demonstrated a significantly high migration rate of 2.7 ± 0.24 µm/min over SCPPPQ1/LAM332-coated surfaces. Our collective data show that this protein complex has the potential to be further developed in designing a bioadhesive to enhance the JE attachment and protect the underlying connective tissue from bacterial invasion. However, its efficacy for wound healing requires further testing in vivo. STATEMENT OF SIGNIFICANCE: This work is the first functional study towards understanding the combined role of the enamel protein SCPPPQ1 and laminin 332 (LAM332) in the epithelial attachment of the gum, the junctional epithelium (JE), to the tooth hydroxyapatite surfaces. Such studies are essential for developing therapeutic approaches to restore the integrity of the JE in the destructive form of gum infection. We have developed a model system that provided the first evidence of the strong interaction between SCPPPQ1 and LAM332 on hydroxyapatite surfaces that favored protein adsorption and subsequently oral epithelial cell attachment and migration. Our collective data strongly suggested using the SCPPPQ1/LAM332 complex to accelerate the reestablishment of the JE after surgical gum removal to facilitate gum regeneration.
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Arefmanesh M, Vuong TV, Nikafshar S, Wallmo H, Nejad M, Master ER. Enzymatic synthesis of kraft lignin-acrylate copolymers using an alkaline tolerant laccase. Appl Microbiol Biotechnol 2022; 106:2969-2979. [PMID: 35449361 PMCID: PMC9064866 DOI: 10.1007/s00253-022-11916-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 03/29/2022] [Accepted: 04/02/2022] [Indexed: 11/28/2022]
Abstract
Abstract Softwood kraft lignin is a major bioresource relevant to the production of sustainable bio-based products. Continued challenges to lignin valorization, however, include poor solubility in organic solvents and in aqueous solutions at neutral pH. Herein, an alkaline tolerant laccase was used to graft acrylate functionalities onto softwood kraft lignin, which is expected to enhance the reactivity of lignin with isocyanate when producing bio-based polyurethanes. Proton nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and high-performance liquid chromatography were used to confirm successful grafting of the acrylate monomer onto lignin and verify the importance of including tert-butyl hydroperoxide as an initiator in the grafting reaction. Laccase-mediated grafting of softwood kraft lignin under alkaline conditions produced lignin products with approximately 30% higher hydroxyl value and higher reactivity toward isocyanate. The reported enzymatic and aqueous process presents an opportunity for the sustainable valorization of softwood kraft lignin. Key points • Softwood kraft lignin displayed high phenolic hydroxyl content, polydispersity index and average molecular weight • Grafting hydroxyethyl acrylate (HEA) monomer onto kraft lignin by laccase was successful at 60 °C and alkaline conditions • Lignin-HEA grafted copolymer showed an increase in total OH value and an increase in average molecular weight Supplementary information The online version contains supplementary material available at 10.1007/s00253-022-11916-z.
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Affiliation(s)
- Maryam Arefmanesh
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Saeid Nikafshar
- Department of Forestry, Michigan State University, 480 Wilson Road, East Lansing, MI, 48824, USA
| | - Henrik Wallmo
- Valmet AB, Regnbågsgatan 6, PO Box 8734, 402 75, Gothenburg, Sweden
| | - Mojgan Nejad
- Department of Forestry, Michigan State University, 480 Wilson Road, East Lansing, MI, 48824, USA.,Department of Chemical Engineering and Material Science, Michigan State University, 428 S Shaw Lane, East Lansing, MI, 48824, USA
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada. .,Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 00076 Aalto, Espoo, Finland.
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Vuong TV, Singh R, Eltis LD, Master ER. The Comparative Abilities of a Small Laccase and a Dye-Decoloring Peroxidase From the Same Bacterium to Transform Natural and Technical Lignins. Front Microbiol 2021; 12:723524. [PMID: 34733245 PMCID: PMC8559727 DOI: 10.3389/fmicb.2021.723524] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 09/23/2021] [Indexed: 11/29/2022] Open
Abstract
The relative ability of the small laccase (sLac) and dye-decoloring peroxidase (DyP2) from Amycolatopsis sp. 75iv2 to transform a variety of lignins was investigated using time-of-flight secondary ion mass spectrometry (ToF-SIMS). The enzymes modified organosolv hardwood lignin to different extents even in the absence of an added mediator. More particularly, sLac decreased the lignin modification metric S (S-lignin)/Ar (total aromatics) by 58% over 16h, while DyP2 lowered this ratio by 31% in the absence of exogenous H2O2. When used on their own, both sLac and DyP2 also modified native lignin present in aspen wood powder, albeit to lesser extents than in the organosolv lignin. The addition of ABTS for sLac and Mn2+ as well as H2O2 for DyP2 led to increased lignin modification in aspen wood powder as reflected by a decrease in the G/Ar metric by up to a further 13%. This highlights the importance of exogenous mediators for transforming lignin within its native matrix. Furthermore, the addition of ABTS reduced the selectivity of sLac for S-lignin over G-lignin, indicating that the mediator also altered the product profiles. Finally, when sLac was included in reactions containing DyP2, in part to generate H2O2in situ, the relative abundance of lignin products differed from individual enzymatic treatments. Overall, these results identify possible routes to tuning lignin modification or delignification through choice of enzyme and mediator. Moreover, the current study expands the application of ToF-SIMS to evaluating enzyme action on technical lignins, which can accelerate the discovery and engineering of industrially relevant enzymes for lignin valorization.
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Affiliation(s)
- Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Rahul Singh
- Department of Microbiology and Immunology, BioProducts Institute, The University of British Columbia, Vancouver, BC, Canada.,Genome British Columbia, Vancouver, BC, Canada
| | - Lindsay D Eltis
- Department of Microbiology and Immunology, BioProducts Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada.,Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland
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Vuong TV, Master ER. Enzymatic upgrading of heteroxylans for added-value chemicals and polymers. Curr Opin Biotechnol 2021; 73:51-60. [PMID: 34311175 DOI: 10.1016/j.copbio.2021.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/27/2021] [Accepted: 07/02/2021] [Indexed: 02/06/2023]
Abstract
Xylan is one of the most abundant, natural polysaccharides, and much recent interest focuses on upgrading heteroxylan to make use of its unique structures and chemistries. Significant progress has been made in the discovery and application of novel enzymes for debranching and modifying heteroxylans. Debranching enzymes include acetylxylan esterases, α-l-arabinofuranosidases and α-dglucuronidases that release side groups from the xylan backbone to recover both biochemicals and less substituted xylans for polymer applications in food packaging or drug delivery systems. Besides esterases and hydrolases, many oxidoreductases including carbohydrate oxidases, lytic polysaccharide monooxygenases, laccases and peroxidases have been also applied to alter different types of xylans for improved physical and chemical properties. This review will highlight the recent discovery and application of enzymes for upgrading xylans for use as added-value chemicals and in functional polymers.
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Affiliation(s)
- Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada; Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland.
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Yan R, Wang W, Vuong TV, Xiu Y, Skarina T, Di Leo R, Gatenholm P, Toriz G, Tenkanen M, Stogios PJ, Master ER. Structural characterization of the family GH115 α-glucuronidase from Amphibacillus xylanus yields insight into its coordinated action with α-arabinofuranosidases. N Biotechnol 2021; 62:49-56. [PMID: 33486119 DOI: 10.1016/j.nbt.2021.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 01/11/2021] [Accepted: 01/16/2021] [Indexed: 01/01/2023]
Abstract
The coordinated action of carbohydrate-active enzymes has mainly been evaluated for the purpose of complete saccharification of plant biomass (lignocellulose) to sugars. By contrast, the coordinated action of accessory hemicellulases on xylan debranching and recovery is less well characterized. Here, the activity of two family GH115 α-glucuronidases (SdeAgu115A from Saccharophagus degradans, and AxyAgu115A from Amphibacillus xylanus) on spruce arabinoglucuronoxylan (AGX) was evaluated in combination with an α-arabinofuranosidase from families GH51 (AniAbf51A, aka E-AFASE from Aspergillus niger) and GH62 (SthAbf62A from Streptomyces thermoviolaceus). The α-arabinofuranosidases boosted (methyl)-glucuronic acid release by SdeAgu115A by approximately 50 % and 30 %, respectively. The impact of the α-arabinofuranosidases on AxyAgu115A activity was comparatively low, motivating its structural characterization. The crystal structure of AxyAgu115A revealed increased length and flexibility of the active site loop compared to SdeAgu115A. This structural difference could explain the ability of AxyAgu115A to accommodate more highly substituted arabinoglucuronoxylan, and inform enzyme selections for improved AGX recovery and use.
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Affiliation(s)
- Ruoyu Yan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Weijun Wang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Yang Xiu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Tatiana Skarina
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Rosa Di Leo
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Paul Gatenholm
- Department of Chemistry and Chemical Engineering, Wallenberg Wood Science Center and Biopolymer Technology, Chalmers University of Technology, Kemivägen 4, Gothenburg, 412 96, Sweden
| | - Guillermo Toriz
- Department of Wood, Cellulose and Paper Research, University of Guadalajara, Guadalajara, 44100, Mexico
| | - Maija Tenkanen
- Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 27, Helsinki, 00014, Finland
| | - Peter J Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada; Department of Bioproducts and Biosystems, Aalto University, FI-00076, Aalto, Kemistintie 1, Espoo, Finland.
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Vuong TV. Natural Products and Their Derivatives with Antibacterial, Antioxidant and Anticancer Activities. Antibiotics (Basel) 2021; 10:antibiotics10010070. [PMID: 33450907 PMCID: PMC7828331 DOI: 10.3390/antibiotics10010070] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 01/12/2021] [Indexed: 11/17/2022] Open
Affiliation(s)
- Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada
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Raji O, Arnling Bååth J, Vuong TV, Larsbrink J, Olsson L, Master ER. The coordinated action of glucuronoyl esterase and α-glucuronidase promotes the disassembly of lignin-carbohydrate complexes. FEBS Lett 2021; 595:351-359. [PMID: 33277689 PMCID: PMC8044923 DOI: 10.1002/1873-3468.14019] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 12/19/2022]
Abstract
Glucuronoxylans represent a significant fraction of woody biomass, and its decomposition is complicated by the presence of lignin–carbohydrate complexes (LCCs). Herein, LCCs from birchwood were used to investigate the potential coordinated action of a glucuronoyl esterase (TtCE15A) and two α‐glucuronidases (SdeAgu115A and AxyAgu115A). When supplementing α‐glucuronidase with equimolar quantities of TtCE15A, total MeGlcpA released after 72 h by SdeAgu115A and AxyAgu115A increased from 52% to 67%, and 61% to 95%, respectively. Based on the combined TtCE15A and AxyAgu115A activities, ~ 34% of MeGlcpA in the extracted birchwood glucuronoxylan was occupied as LCCs. Notably, insoluble LCC fractions reduced soluble α‐glucuronidase concentrations by up to 70%, whereas reduction in soluble TtCE15A was less than 30%, indicating different tendencies to adsorb onto the LCC substrate.
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Affiliation(s)
- Olanrewaju Raji
- Department of Chemical Engineering and Applied Science, University of Toronto, ON, Canada
| | - Jenny Arnling Bååth
- Department of Biology and Biological Engineering, Wallenberg Wood Science Center, Chalmers University of Technology, Gothenburg, Sweden
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Science, University of Toronto, ON, Canada
| | - Johan Larsbrink
- Department of Biology and Biological Engineering, Wallenberg Wood Science Center, Chalmers University of Technology, Gothenburg, Sweden
| | - Lisbeth Olsson
- Department of Biology and Biological Engineering, Wallenberg Wood Science Center, Chalmers University of Technology, Gothenburg, Sweden
| | - Emma R Master
- Department of Chemical Engineering and Applied Science, University of Toronto, ON, Canada.,Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland
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Arefmanesh M, Vuong TV, Mobley JK, Alinejad M, Master ER, Nejad M. Bromide-Based Ionic Liquid Treatment of Hardwood Organosolv Lignin Yielded a More Reactive Biobased Polyol. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c03718] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Maryam Arefmanesh
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Thu V. Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Justin K. Mobley
- Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, Kentucky 40506, United States
| | - Mona Alinejad
- Department of Forestry, Michigan State University, 480 Wilson Road, East Lansing, Michigan 48824, United States
| | - Emma R. Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
- Department of Bioproducts and Biosystems, Aalto University, Aalto, Kemistintie 1, Espoo FI-00076, Finland
| | - Mojgan Nejad
- Department of Forestry, Michigan State University, 480 Wilson Road, East Lansing, Michigan 48824, United States
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Vuong TV, Master ER. Enzymatic production of 4- O-methyl d-glucaric acid from hardwood xylan. Biotechnol Biofuels 2020; 13:51. [PMID: 32190116 PMCID: PMC7071571 DOI: 10.1186/s13068-020-01691-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 02/27/2020] [Indexed: 05/10/2023]
Abstract
BACKGROUND Dicarboxylic acids offer several applications in detergent builder and biopolymer fields. One of these acids, 4-O-methyl d-glucaric acid, could potentially be produced from glucuronoxylans, which are a comparatively underused fraction of wood and agricultural biorefineries. RESULTS Accordingly, an enzymatic pathway was developed that combines AxyAgu115A, a GH115 α-glucuronidase from Amphibacillus xylanus, and GOOX, an AA7 gluco-oligosaccharide oxidase from Sarocladium strictum, to produce this bio-based chemical from glucuronoxylan. AxyAgu115A was able to release almost all 4-O-methyl d-glucuronic acid from glucuronoxylan while a GOOX variant, GOOX-Y300A, could convert 4-O-methyl d-glucuronic acid to the corresponding glucaric acid at a yield of 62%. Both enzymes worked effectively at alkaline conditions that increase xylan solubility. Given the sensitivity of AxyAgu115A to hydrogen peroxide and optimal performance of GOOX-Y300A at substrate concentrations above 20 mM, the two-step enzyme pathway was demonstrated as a sequential, one-pot reaction. Additionally, the resulting xylan was easily recovered from the one-pot reaction, and it was enzymatically hydrolysable. CONCLUSIONS The pathway in this study requires only two enzymes while avoiding a supplementation of costly cofactors. This cell-free approach provides a new strategy to make use of the underutilized hemicellulose stream from wood and agricultural biorefineries.
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Affiliation(s)
- Thu V. Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON Canada
| | - Emma R. Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON Canada
- Department of Bioproducts and Biosystems, Aalto University, Aalto, Kemistintie 1, 00076 Espoo, Finland
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13
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MacCormick B, Vuong TV, Master ER. Chemo-enzymatic Synthesis of Clickable Xylo-oligosaccharide Monomers from Hardwood 4-O-Methylglucuronoxylan. Biomacromolecules 2018; 19:521-530. [PMID: 29338223 DOI: 10.1021/acs.biomac.7b01642] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A chemo-enzymatic pathway was developed to transform 4-O-methylglucuronic acid (MeGlcpA) containing xylo-oligosaccharides from beechwood into clickable monomers capable of polymerizing at room temperature and in aqueous conditions to form unique polytriazoles. While the gluco-oligosaccharide oxidase (GOOX) from Sarocladium strictum was used to oxidize C6-propargylated oligosaccharides, the acid-amine coupling reagents 1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide (EDAC) and 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) were employed and compared for their ability to append click functionalities to carboxylic acid groups of enzyme-treated oligosaccharides. While DMT-MM was a superior coupling reagent for this application, a triazine side product was observed during C-1 amidation. Resulting bifunctional xylo-oligosaccharide monomers were polymerized using a Cu(I) catalyst, forming a soft gel which was characterized by 1H NMR, confirming the triazole product.
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Affiliation(s)
- Benjamin MacCormick
- Department of Chemical Engineering and Applied Chemistry, University of Toronto , Toronto, Ontario M5S 3E5, Canada
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto , Toronto, Ontario M5S 3E5, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto , Toronto, Ontario M5S 3E5, Canada.,Department of Bioproducts and Biosystems, Aalto University , Kemistintie 1, FI-00076 Aalto, Espoo, Finland
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Yan R, Vuong TV, Wang W, Master ER. Action of a GH115 α-glucuronidase from Amphibacillus xylanus at alkaline condition promotes release of 4-O-methylglucopyranosyluronic acid from glucuronoxylan and arabinoglucuronoxylan. Enzyme Microb Technol 2017. [PMID: 28648176 DOI: 10.1016/j.enzmictec.2017.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Glucuronic acid and/or 4-O-methyl-glucuronic acid (GlcA/MeGlcA) are substituents of the main xylans present in hardwoods, conifers, and many cereal grains. α-Glucuronidases from glycoside hydrolase family GH115 can target GlcA/MeGlcA from both internally and terminally substituted regions of xylans. The current study describes the first GH115 α-glucuronidase, AxyAgu115A, from the alkaliphilic organism Amphilbacillus xylanus. AxyAgu115A was active in a wide pH range, and demonstrated better performance in alkaline condition compared to other characterized GH115 α-glucuronidases, which generally show optimal activity in acidic conditions. Specifically, its relative activity between pH 5.0 and pH 8.5 was above 80%, and was 35% of maximum at pH 10.5; although the enzyme lost 30% and 80% relative residual activity after 24-h pre-incubation at pH 9 and pH 10, respectively. AxyAgu115A was also similarly active towards glucuronoxylan as well as comparatively complex xylans such as spruce arabinoglucurunoxylan. Accommodation of complex xylans was supported by docking analyses that predicted accessibility of AxyAgu115A to branched xylo-oligosaccharides. MeGlcA release by AxyAgu115A from each xylan sample was increased by up to 30% by performing the reaction at pH 11.0 rather than pH 4.0, revealing applied benefits of AxyAgu115A for xylan recovery and processing.
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Affiliation(s)
- Ruoyu Yan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada.
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada.
| | - Weijun Wang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada.
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada.
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15
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Vuong TV, Liu B, Sandgren M, Master ER. Microplate-Based Detection of Lytic Polysaccharide Monooxygenase Activity by Fluorescence-Labeling of Insoluble Oxidized Products. Biomacromolecules 2017; 18:610-616. [DOI: 10.1021/acs.biomac.6b01790] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thu V. Vuong
- Department
of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Bing Liu
- Department
of Molecular Sciences, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
| | - Mats Sandgren
- Department
of Molecular Sciences, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
| | - Emma R. Master
- Department
of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
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16
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Vuong TV, Foumani M, MacCormick B, Kwan R, Master ER. Direct comparison of gluco-oligosaccharide oxidase variants and glucose oxidase: substrate range and H 2O 2 stability. Sci Rep 2016; 6:37356. [PMID: 27869125 PMCID: PMC5116756 DOI: 10.1038/srep37356] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 10/27/2016] [Indexed: 12/01/2022] Open
Abstract
Glucose oxidase (GO) activity is generally restricted to glucose and is susceptible to inactivation by H2O2. By comparison, the Y300A variant of gluco-oligosaccharide oxidase (GOOX) from Sarocladium strictum showed broader substrate range and higher H2O2 stability. Specifically, Y300A exhibited up to 40 times higher activity on all tested sugars except glucose, compared to GO. Moreover, fusion of the Y300A variant to a family 22 carbohydrate binding module from Clostridium thermocellum (CtCBM22A) nearly doubled its catalytic efficiency on glucose, while retaining significant activity on oligosaccharides. In the presence of 200 mM of H2O2, the recombinant CtCBM22A_Y300A retained 80% of activity on glucose and 100% of activity on cellobiose, the preferred substrate for this enzyme. By contrast, a commercial glucose oxidase reported to contain ≤0.1 units catalase/ mg protein, retained 60% activity on glucose under the same conditions. GOOX variants appear to undergo a different mechanism of inactivation, as a loss of histidine instead of methionine was observed after H2O2 incubation. The addition of CtCBM22A also promoted functional binding of the fusion enzyme to xylan, facilitating its simultaneous purification and immobilization using edible oat spelt xylan, which might benefit the usage of this enzyme preparation in food and baking applications.
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Affiliation(s)
- Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Maryam Foumani
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Benjamin MacCormick
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Rachel Kwan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
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17
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Wang W, Yan R, Nocek BP, Vuong TV, Di Leo R, Xu X, Cui H, Gatenholm P, Toriz G, Tenkanen M, Savchenko A, Master ER. Biochemical and Structural Characterization of a Five-domain GH115 α-Glucuronidase from the Marine Bacterium Saccharophagus degradans 2-40T. J Biol Chem 2016; 291:14120-14133. [PMID: 27129264 DOI: 10.1074/jbc.m115.702944] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Indexed: 01/01/2023] Open
Abstract
Glucuronic acid (GlcAp) and/or methylglucuronic acid (MeGlcAp) decorate the major forms of xylan in hardwood and coniferous softwoods as well as many cereal grains. Accordingly, the complete utilization of glucuronoxylans or conversion to sugar precursors requires the action of main chain xylanases as well as α-glucuronidases that release the α- (1→2)-linked (Me)GlcAp side groups. Herein, a family GH115 enzymefrom the marine bacterium Saccharophagus degradans 2-40(T), SdeAgu115A, demonstrated activity toward glucuronoxylan and oligomers thereof with preference toward MeGlcAp linked to internal xylopyranosyl residues. Unique biochemical characteristics of NaCl activation were also observed. The crystal structure of SdeAgu115A revealed a five-domain architecture, with an additional insertion C(+) domain that had significant impact on the domain arrangement of SdeAgu115A monomer and its dimerization. The participation of domain C(+) in substrate binding was supported by reduced substrate inhibition upon introducing W773A, W689A, and F696A substitutions within this domain. In addition to Asp-335, the catalytic essentiality of Glu-216 was revealed by site-specific mutagenesis. A primary sequence analysis suggested that the SdeAgu115A architecture is shared by more than half of GH115 members, thus defining a distinct archetype for GH115 enzymes.
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Affiliation(s)
- Weijun Wang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Ruoyu Yan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Boguslaw P Nocek
- Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Rosa Di Leo
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Xiaohui Xu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Hong Cui
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Paul Gatenholm
- Department of Chemistry and Chemical Engineering, Wallenberg Wood Science Center and Biopolymer Technology, Chalmers University of Technology, Kemivägen 4, Gothenburg 412 96, Sweden
| | - Guillermo Toriz
- Department of Chemistry and Chemical Engineering, Wallenberg Wood Science Center and Biopolymer Technology, Chalmers University of Technology, Kemivägen 4, Gothenburg 412 96, Sweden,; Department of Wood, Cellulose and Paper Research, University of Guadalajara, Guadalajara 44100, Mexico
| | - Maija Tenkanen
- Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 27, Helsinki 00014, Finland
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada,.
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada,.
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Mollerup F, Parikka K, Vuong TV, Tenkanen M, Master E. Influence of a family 29 carbohydrate binding module on the activity of galactose oxidase from Fusarium graminearum. Biochim Biophys Acta Gen Subj 2015; 1860:354-62. [PMID: 26518347 DOI: 10.1016/j.bbagen.2015.10.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 10/02/2015] [Accepted: 10/23/2015] [Indexed: 11/26/2022]
Abstract
BACKGROUND Galactose oxidase (GaO) selectively oxidizes the primary hydroxyl of galactose to a carbonyl, facilitating targeted chemical derivatization of galactose-containing polysaccharides, leading to renewable polymers with tailored physical and chemical properties. Here we investigate the impact of a family 29 glucomannan binding module on the activity and binding of GaO towards various polysaccharides. Specifically, CBM29-1-2 from Piromyces equi was separately linked to the N- and C-termini of GaO. RESULTS Both GaO-CBM29 and CBM29-GaO were successfully expressed in Pichia pastoris, and demonstrated enhanced binding to galactomannan, galactoglucomannan and galactoxyloglucan. The position of the CBM29 fusion affected the enzyme function. Particularly, C-terminal fusion led to greatest increases in galactomannan binding and catalytic efficiency, where relative to wild-type GaO, kcat/Km values increased by 7.5 and 19.8 times on guar galactomannan and locust bean galactomannan, respectively. The fusion of CBM29 also induced oligomerization of GaO-CBM29. MAJOR CONCLUSIONS Similar to impacts of cellulose-binding modules associated with cellulolytic enzymes, increased substrate binding impeded the action of GaO fusions on more concentrated preparations of galactomannan, galactoglucomannan and galactoxyloglucan; this was especially true for GaO-CBM29. Given the N-terminal positioning of the native galactose-binding CBM32 in GaO, the varying impacts of N-terminal versus C-terminal fusion of CBM29-1-2 may reflect competing action of neighboring CBMs. GENERAL SIGNIFICANCE This study thoroughly examines and discusses the effects of CBM fusion to non-lignocellulytic enzymes on soluble polysaccharides. Herein kinetics of GaO on galactose containing polysaccharides is presented for the first time.
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Affiliation(s)
- Filip Mollerup
- Department of Biotechnology and Chemical Technology, Aalto University, 00076 Aalto, Finland
| | - Kirsti Parikka
- Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 27, Helsinki 00014, Finland
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Maija Tenkanen
- Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 27, Helsinki 00014, Finland
| | - Emma Master
- Department of Biotechnology and Chemical Technology, Aalto University, 00076 Aalto, Finland; Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada.
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19
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Foumani M, Vuong TV, MacCormick B, Master ER. Enhanced Polysaccharide Binding and Activity on Linear β-Glucans through Addition of Carbohydrate-Binding Modules to Either Terminus of a Glucooligosaccharide Oxidase. PLoS One 2015; 10:e0125398. [PMID: 25932926 PMCID: PMC4416756 DOI: 10.1371/journal.pone.0125398] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/23/2015] [Indexed: 02/07/2023] Open
Abstract
The gluco-oligosaccharide oxidase from Sarocladium strictum CBS 346.70 (GOOX) is a single domain flavoenzyme that favourably oxidizes gluco- and xylo- oligosaccharides. In the present study, GOOX was shown to also oxidize plant polysaccharides, including cellulose, glucomannan, β-(1→3,1→4)-glucan, and xyloglucan, albeit to a lesser extent than oligomeric substrates. To improve GOOX activity on polymeric substrates, three carbohydrate binding modules (CBMs) from Clostridium thermocellum, namely CtCBM3 (type A), CtCBM11 (type B), and CtCBM44 (type B), were separately appended to the amino and carboxy termini of the enzyme, generating six fusion proteins. With the exception of GOOX-CtCBM3 and GOOX-CtCBM44, fusion of the selected CBMs increased the catalytic activity of the enzyme (kcat) on cellotetraose by up to 50%. All CBM fusions selectively enhanced GOOX binding to soluble and insoluble polysaccharides, and the immobilized enzyme on a solid cellulose surface remained stable and active. In addition, the CBM fusions increased the activity of GOOX on soluble glucomannan by up to 30 % and on insoluble crystalline as well as amorphous cellulose by over 50 %.
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Affiliation(s)
- Maryam Foumani
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Thu V. Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Benjamin MacCormick
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Emma R. Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
- * E-mail:
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20
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Abstract
Bioprocesses capable of producing large scales of resveratrol at nutraceutical grade are in demand. This study herein investigated treatment strategies to induce the production of resveratrol in Vitis vinifera L. cell suspension cultures. Among seven investigated elicitors, jasmonic acid (JA), salicylic acid, β-glucan (GLU), and chitosan enhanced the production of intracellular resveratrol manyfold. The combined treatment of JA and GLU increased extracellular resveratrol production by up to tenfold. The application of Amberlite XAD-7 resin for in situ removal and artificial storage of secreted resveratrol further increased resveratrol production by up to four orders of magnitude. The level of resveratrol produced in response to the combined treatment with 200 g/L XAD-7, 10 μM JA and 1 mg/mL GLU was approximately 2400 mg/L, allowing the production of resveratrol at an industrial scale. The high yield of resveratrol is due to the involvement of a number of mechanisms working in concert.
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Affiliation(s)
- Thu V Vuong
- Department of Medical Biotechnology, School of Medicine, Flinders University, Adelaide 5042, Australia.,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Chris Franco
- Department of Medical Biotechnology, School of Medicine, Flinders University, Adelaide 5042, Australia
| | - Wei Zhang
- Department of Medical Biotechnology, School of Medicine, Flinders University, Adelaide 5042, Australia
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21
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Vuong TV, Vesterinen AH, Foumani M, Juvonen M, Seppälä J, Tenkanen M, Master ER. Xylo- and cello-oligosaccharide oxidation by gluco-oligosaccharide oxidase from Sarocladium strictum and variants with reduced substrate inhibition. Biotechnol Biofuels 2013; 6:148. [PMID: 24119501 PMCID: PMC4015748 DOI: 10.1186/1754-6834-6-148] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 10/04/2013] [Indexed: 05/21/2023]
Abstract
BACKGROUND The oxidation of carbohydrates from lignocellulose can facilitate the synthesis of new biopolymers and biochemicals, and also reduce sugar metabolism by lignocellulolytic microorganisms, reserving aldonates for fermentation to biofuels. Although oxidoreductases that oxidize cellulosic hydrolysates have been well characterized, none have been reported to oxidize substituted or branched xylo-oligosaccharides. Moreover, this is the first report that identifies amino acid substitutions leading to GOOX variants with reduced substrate inhibition. RESULTS The recombinant wild type gluco-oligosaccharide oxidase (GOOX) from the fungus Sarocladium strictum, along with variants that were generated by site-directed mutagenesis, retained the FAD cofactor, and showed high activity on cello-oligosaccharide and xylo-oligosaccharides, including substituted and branched xylo-oligosaccharides. Mass spectrometric analyses confirmed that GOOX introduces one oxygen atom to oxidized products, and 1H NMR and tandem mass spectrometry analysis confirmed that oxidation was restricted to the anomeric carbon. The A38V mutation, which is close to a predicted divalent ion-binding site in the FAD-binding domain of GOOX but 30 Å away from the active site, significantly increased the kcat and catalytic efficiency of the enzyme on all oligosaccharides. Eight amino acid substitutions were separately introduced to the substrate-binding domain of GOOX-VN (at positions Y72, E247, W351, Q353 and Q384). In all cases, the Km of the enzyme variant was higher than that of GOOX, supporting the role of corresponding residues in substrate binding. Most notably, W351A increased Km values by up to two orders of magnitude while also increasing kcat up to 3-fold on cello- and xylo-oligosaccharides and showing no substrate inhibition. CONCLUSIONS This study provides further evidence that S. strictum GOOX has broader substrate specificity than the enzyme name implies, and that substrate inhibition can be reduced by removing aromatic side chains in the -2 binding subsite. Of the enzyme variants, W351A might be particularly advantageous when oxidizing oligosaccharides present at high substrate concentrations often experienced in industrial processes.
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Affiliation(s)
- Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Arja-Helena Vesterinen
- Department of Biotechnology and Chemical Technology, Aalto University, Kemistintie 1 D1, Espoo 02150, Finland
| | - Maryam Foumani
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Minna Juvonen
- Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 27, Helsinki 00014, Finland
| | - Jukka Seppälä
- Department of Biotechnology and Chemical Technology, Aalto University, Kemistintie 1 D1, Espoo 02150, Finland
| | - Maija Tenkanen
- Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 27, Helsinki 00014, Finland
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
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Wu M, Bu L, Vuong TV, Wilson DB, Crowley MF, Sandgren M, Ståhlberg J, Beckham GT, Hansson H. Loop motions important to product expulsion in the Thermobifida fusca glycoside hydrolase family 6 cellobiohydrolase from structural and computational studies. J Biol Chem 2013; 288:33107-17. [PMID: 24085303 DOI: 10.1074/jbc.m113.502765] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellobiohydrolases (CBHs) are typically major components of natural enzyme cocktails for biomass degradation. Their active sites are enclosed in a tunnel, enabling processive hydrolysis of cellulose chains. Glycoside hydrolase Family 6 (GH6) CBHs act from nonreducing ends by an inverting mechanism and are present in many cellulolytic fungi and bacteria. The bacterial Thermobifida fusca Cel6B (TfuCel6B) exhibits a longer and more enclosed active site tunnel than its fungal counterparts. Here, we determine the structures of two TfuCel6B mutants co-crystallized with cellobiose, D274A (catalytic acid), and the double mutant D226A/S232A, which targets the putative catalytic base and a conserved serine that binds the nucleophilic water. The ligand binding and the structure of the active site are retained when compared with the wild type structure, supporting the hypothesis that these residues are directly involved in catalysis. One structure exhibits crystallographic waters that enable construction of a model of the α-anomer product after hydrolysis. Interestingly, the product sites of TfuCel6B are completely enclosed by an "exit loop" not present in fungal GH6 CBHs and by an extended "bottom loop". From the structures, we hypothesize that either of the loops enclosing the product subsites in the TfuCel6B active site tunnel must open substantially for product release. With simulation, we demonstrate that both loops can readily open to allow product release with equal probability in solution or when the enzyme is engaged on cellulose. Overall, this study reveals new structural details of GH6 CBHs likely important for functional differences among enzymes from this important family.
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Affiliation(s)
- Miao Wu
- From the Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
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Foumani M, Vuong TV, Master ER. Altered substrate specificity of the gluco-oligosaccharide oxidase from Acremonium strictum. Biotechnol Bioeng 2011; 108:2261-9. [PMID: 21455933 DOI: 10.1002/bit.23149] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 03/05/2011] [Accepted: 03/14/2011] [Indexed: 11/08/2022]
Abstract
A gluco-oligosaccharide oxidase (GOOX) from Acremonium strictum type strain CBS 346.70 was cloned and expressed in Pichia pastoris. The recombinant protein, GOOX-VN, contained fifteen amino acid substitutions compared with the previously reported A. strictum GOOX. These two enzymes share 97% sequence identity; however, only GOOX-VN oxidized xylose, galactose, and N-acetylglucosamine. Besides monosaccharides, GOOX-VN oxidized xylo-oligosaccharides, including xylobiose and xylotriose with similar catalytic efficiency as for cello-oligosaccharides. Of three mutant enzymes that were created in GOOX-VN to improve substrate specificity, Y300A and Y300N doubled kcat values for monosaccharide and oligosaccharide substrates. With this novel substrate specificity, GOOX-VN and its variants are particularly valuable for oxidative modification of cello- and xylo-oligosaccharides.
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Affiliation(s)
- Maryam Foumani
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, Canada M5S 3E5; telephone: +1-416-946-7861; fax: +1-416-978-8605
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24
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Abstract
Recent studies have shown that a number of glycoside hydrolase families do not follow the classical catalytic mechanisms, as they lack a typical catalytic base/nucleophile. A variety of mechanisms are used to replace this function, including substrate-assisted catalysis, a network of several residues, and the use of non-carboxylate residues or exogenous nucleophiles. Removal of the catalytic base/nucleophile by mutation can have a profound impact on substrate specificity, producing enzymes with completely new functions.
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Affiliation(s)
- Thu V Vuong
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
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