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Geiss A, Reichhart TMB, Pejker B, Plattner E, Herzog PL, Schulz C, Ludwig R, Felice AKG, Haltrich D. Engineering the Turnover Stability of Cellobiose Dehydrogenase toward Long-Term Bioelectronic Applications. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2021; 9:7086-7100. [PMID: 34306835 PMCID: PMC8296668 DOI: 10.1021/acssuschemeng.1c01165] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 04/16/2021] [Indexed: 05/09/2023]
Abstract
Cellobiose dehydrogenase (CDH) is an attractive oxidoreductase for bioelectrochemical applications. Its two-domain structure allows the flavoheme enzyme to establish direct electron transfer to biosensor and biofuel cell electrodes. Yet, the application of CDH in these devices is impeded by its limited stability under turnover conditions. In this work, we aimed to improve the turnover stability of CDH by semirational, high-throughput enzyme engineering. We screened 13 736 colonies in a 96-well plate setup for improved turnover stability and selected 11 improved variants. Measures were taken to increase the reproducibility and robustness of the screening setup, and the statistical evaluation demonstrates the validity of the procedure. The selected CDH variants were expressed in shaking flasks and characterized in detail by biochemical and electrochemical methods. Two mechanisms contributing to turnover stability were found: (i) replacement of methionine side chains prone to oxidative damage and (ii) the reduction of oxygen reactivity achieved by an improved balance of the individual reaction rates in the two CDH domains. The engineered CDH variants hold promise for the application in continuous biosensors or biofuel cells, while the deduced mechanistic insights serve as a basis for future enzyme engineering approaches addressing the turnover stability of oxidoreductases in general.
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Affiliation(s)
- Andreas
F. Geiss
- Biocatalysis
and Biosensing Laboratory, Department of Food Science and Technology, BOKU − University of Natural Resources and
Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Thomas M. B. Reichhart
- Biocatalysis
and Biosensing Laboratory, Department of Food Science and Technology, BOKU − University of Natural Resources and
Life Sciences, Muthgasse 18, 1190 Vienna, Austria
- DirectSens
Biosensors GmbH, Am Rosenbühel
38, 3400 Klosterneuburg, Austria
| | - Barbara Pejker
- Biocatalysis
and Biosensing Laboratory, Department of Food Science and Technology, BOKU − University of Natural Resources and
Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Esther Plattner
- DirectSens
Biosensors GmbH, Am Rosenbühel
38, 3400 Klosterneuburg, Austria
| | - Peter L. Herzog
- DirectSens
Biosensors GmbH, Am Rosenbühel
38, 3400 Klosterneuburg, Austria
| | - Christopher Schulz
- DirectSens
Biosensors GmbH, Am Rosenbühel
38, 3400 Klosterneuburg, Austria
| | - Roland Ludwig
- Biocatalysis
and Biosensing Laboratory, Department of Food Science and Technology, BOKU − University of Natural Resources and
Life Sciences, Muthgasse 18, 1190 Vienna, Austria
- DirectSens
Biosensors GmbH, Am Rosenbühel
38, 3400 Klosterneuburg, Austria
| | - Alfons K. G. Felice
- DirectSens
Biosensors GmbH, Am Rosenbühel
38, 3400 Klosterneuburg, Austria
- E-mail: . Telephone: +436505000167
| | - Dietmar Haltrich
- Biocatalysis
and Biosensing Laboratory, Department of Food Science and Technology, BOKU − University of Natural Resources and
Life Sciences, Muthgasse 18, 1190 Vienna, Austria
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Herzog PL, Borghi E, Traxlmayr MW, Obinger C, Sikes HD, Peterbauer CK. Developing a cell-bound detection system for the screening of oxidase activity using the fluorescent peroxide sensor roGFP2-Orp1. Protein Eng Des Sel 2020; 33:gzaa019. [PMID: 32930800 PMCID: PMC7720637 DOI: 10.1093/protein/gzaa019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 06/02/2020] [Accepted: 07/08/2020] [Indexed: 11/14/2022] Open
Abstract
Accurate yet efficient high-throughput screenings have emerged as essential technology for enzyme engineering via directed evolution. Modern high-throughput screening platforms for oxidoreductases are commonly assisted by technologies such as surface display and rely on emulsification techniques to facilitate single-cell analysis via fluorescence-activated cell sorting. Empowered by the dramatically increased throughput, the screening of significantly larger sequence spaces in acceptable time frames is achieved but usually comes at the cost of restricted applicability. In this work, we tackle this problem by utilizing roGFP2-Orp1 as a fluorescent one-component detection system for enzymatic H2O2 formation. We determined the kinetic parameters of the roGFP2-Orp1 reaction with H2O2 and established an efficient immobilization technique for the sensor on Saccharomyces cerevisiae cells employing the lectin Concanavalin A. This allowed to realize a peroxide-sensing shell on enzyme-displaying cells, a system that was successfully employed to screen for H2O2 formation of enzyme variants in a whole-cell setting.
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Affiliation(s)
- P L Herzog
- Food Biotechnology Laboratory, Department of Food Science and Technology, BOKU – University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria
| | - E Borghi
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 287, 41124 Modena, Italy
| | - M W Traxlmayr
- Institute of Biochemistry, Department of Chemistry, BOKU – University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - C Obinger
- Institute of Biochemistry, Department of Chemistry, BOKU – University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - H D Sikes
- Department of Chemical Engineering, MIT – Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge 02139, MA, USA
| | - C K Peterbauer
- Food Biotechnology Laboratory, Department of Food Science and Technology, BOKU – University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria
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Alteration of Electron Acceptor Preferences in the Oxidative Half-Reaction of Flavin-Dependent Oxidases and Dehydrogenases. Int J Mol Sci 2020; 21:ijms21113797. [PMID: 32471202 PMCID: PMC7312611 DOI: 10.3390/ijms21113797] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/22/2020] [Accepted: 05/24/2020] [Indexed: 11/30/2022] Open
Abstract
In this review, recent progress in the engineering of the oxidative half-reaction of flavin-dependent oxidases and dehydrogenases is discussed, considering their current and future applications in bioelectrochemical studies, such as for the development of biosensors and biofuel cells. There have been two approaches in the studies of oxidative half-reaction: engineering of the oxidative half-reaction with oxygen, and engineering of the preference for artificial electron acceptors. The challenges for engineering oxidative half-reactions with oxygen are further categorized into the following approaches: (1) mutation to the putative residues that compose the cavity where oxygen may be located, (2) investigation of the vicinities where the reaction with oxygen may take place, and (3) investigation of possible oxygen access routes to the isoalloxazine ring. Among these approaches, introducing a mutation at the oxygen access route to the isoalloxazine ring represents the most versatile and effective strategy. Studies to engineer the preference of artificial electron acceptors are categorized into three different approaches: (1) engineering of the charge at the residues around the substrate entrance, (2) engineering of a cavity in the vicinity of flavin, and (3) decreasing the glycosylation degree of enzymes. Among these approaches, altering the charge in the vicinity where the electron acceptor may be accessed will be most relevant.
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Abrera AT, Sützl L, Haltrich D. Pyranose oxidase: A versatile sugar oxidoreductase for bioelectrochemical applications. Bioelectrochemistry 2019; 132:107409. [PMID: 31821902 DOI: 10.1016/j.bioelechem.2019.107409] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 10/09/2019] [Accepted: 10/15/2019] [Indexed: 02/08/2023]
Abstract
Pyranose oxidase (POx) is an FAD-dependent oxidoreductase, and like glucose oxidase (GOx) it is a member of the glucose-methanol-choline (GMC) superfamily of oxidoreductases. POx oxidizes several monosaccharides including D-glucose, D-galactose, and D-xylose, while concurrently oxygen is reduced to hydrogen peroxide. In addition to this oxidase activity, POx shows pronounced activity with alternative electron acceptors that include various quinones or (complexed) metal ions. Even though POx in general shows properties that are more favourable than those of GOx (e.g., a considerably higher catalytic efficiency (kcat/Km) for D-glucose, significantly lower Michaelis constants Km for D-glucose, reactivity with both anomeric forms of D-glucose) it is much less frequently used for both biosensor and biofuel cell applications than GOx. POx has been applied in biosensing of D-glucose, D-galactose, and D-xylose, and in combination with α-glucosidase also maltose. An attractive application is in biosensors constructed for the measurement of 1,5-anhydro-D-glucitol, a recognised biomarker in diabetes. Bioelectrochemical applications of POx had been restricted to enzymes of fungal origin. The recent discovery and characterisation of POx from bacterial sources, which show properties that are very distinct from the fungal enzymes, might open new possibilities for further applications in bioelectrochemistry.
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Affiliation(s)
- Annabelle T Abrera
- Food Biotechnology Laboratory, Department of Food Science and Technology, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 11, A-1190 Wien, Austria; University of the Philippines Los Baños, College Laguna, Philippines
| | - Leander Sützl
- Food Biotechnology Laboratory, Department of Food Science and Technology, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 11, A-1190 Wien, Austria; Doctoral Programme BioToP - Biomolecular Technology of Proteins, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 18, A-1190 Wien, Austria
| | - Dietmar Haltrich
- Food Biotechnology Laboratory, Department of Food Science and Technology, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 11, A-1190 Wien, Austria; Doctoral Programme BioToP - Biomolecular Technology of Proteins, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 18, A-1190 Wien, Austria.
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Abrera AT, Chang H, Kracher D, Ludwig R, Haltrich D. Characterization of pyranose oxidase variants for bioelectrocatalytic applications. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1868:140335. [PMID: 31785381 PMCID: PMC6949865 DOI: 10.1016/j.bbapap.2019.140335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/30/2019] [Accepted: 11/25/2019] [Indexed: 11/28/2022]
Abstract
Pyranose oxidase (POx) catalyzes the oxidation of d-glucose to 2-ketoglucose with concurrent reduction of oxygen to H2O2. POx from Trametes ochracea (ToPOx) is known to react with alternative electron acceptors including 1,4-benzoquinone (1,4-BQ), 2,6-dichlorophenol indophenol (DCPIP), and the ferrocenium ion. In this study, enzyme variants with improved electron acceptor turnover and reduced oxygen turnover were characterized as potential anode biocatalysts. Pre-steady-state kinetics of the oxidative half-reaction of ToPOx variants T166R, Q448H, L545C, and L547R with these alternative electron acceptors were evaluated using stopped-flow spectrophotometry. Higher kinetic constants were observed as compared to the wild-type ToPOx for some of the variants. Subsequently, the variants were immobilized on glassy carbon electrodes. Cyclic voltammetry measurements were performed to measure the electrochemical responses of these variants with glucose as substrate in the presence of 1,4-BQ, DCPIP, or ferrocene methanol as redox mediators. High catalytic efficiencies (Imaxapp/KMapp) compared to the wild-type POx proved the potential of these variants for future bioelectrocatalytic applications, in biosensors or biofuel cells. Among the variants, L545C showed the most desirable properties as determined kinetically and electrochemically. Pyranose oxidase (POx) shows attractive features for bioelectrocatalysis. Trametes ochracea POx variant L545C is most promising for these applications. Rapid kinetics experiments give good predictions for performance on an electrode.
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Affiliation(s)
- Annabelle T Abrera
- Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, A-1190 Vienna, Austria; University of the Philippines Los Baños, College Laguna, Los Baños, Philippines
| | - Hucheng Chang
- Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, A-1190 Vienna, Austria
| | - Daniel Kracher
- Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, A-1190 Vienna, Austria
| | - Roland Ludwig
- Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, A-1190 Vienna, Austria
| | - Dietmar Haltrich
- Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, A-1190 Vienna, Austria.
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Wongnate T, Surawatanawong P, Chuaboon L, Lawan N, Chaiyen P. The Mechanism of Sugar C−H Bond Oxidation by a Flavoprotein Oxidase Occurs by a Hydride Transfer Before Proton Abstraction. Chemistry 2019; 25:4460-4471. [DOI: 10.1002/chem.201806078] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/16/2019] [Indexed: 11/06/2022]
Affiliation(s)
- Thanyaporn Wongnate
- School of Biomolecular Science & EngineeringVidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley Rayong 21210 Thailand
| | - Panida Surawatanawong
- Department of Chemistry and Center of Excellence, for Innovation in ChemistryMahidol University Bangkok 10400 Thailand
| | - Litavadee Chuaboon
- Department of Biochemistry and Center for Excellence, in Protein and Enzyme Technology, Faculty of ScienceMahidol University Bangkok 10400 Thailand
| | - Narin Lawan
- Department of Chemistry, Faculty of ScienceChiang Mai University Chiang Mai 50200 Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science & EngineeringVidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley Rayong 21210 Thailand
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