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Serrano A, Cinca-Fernando P, Carro J, Velázquez-Campoy A, Martínez-Júlvez M, Martínez ÁT, Ferreira P. Unveiling the kinetic versatility of aryl-alcohol oxidases with different electron acceptors. Front Bioeng Biotechnol 2024; 12:1440598. [PMID: 39161354 PMCID: PMC11330772 DOI: 10.3389/fbioe.2024.1440598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 07/22/2024] [Indexed: 08/21/2024] Open
Abstract
Introduction: Aryl-alcohol oxidase (AAO) shows a pronounced duality as oxidase and dehydrogenase similar to that described for other glucose-methanol-choline (GMC) oxidase/dehydrogenase superfamily proteins involved in lignocellulose decomposition. In this work, we detail the overall mechanism of AAOs from Pleurotus eryngii and Bjerkandera adusta for catalyzing the oxidation of natural aryl-alcohol substrates using either oxygen or quinones as electron acceptors and describe the crystallographic structure of AAO from B. adusta in complex with a product analogue. Methods: Kinetic studies with 4-methoxybenzyl and 3-chloro-4- methoxybenzyl alcohols, including both transient-state and steady-state analyses, along with interaction studies, provide insight into the oxidase and dehydrogenase mechanisms of these enzymes. Moreover, the resolution of the crystal structure of AAO from B. adusta allowed us to compare their overall folding and the structure of the active sites of both AAOs in relation to their activities. Results and Discussion: Although both enzymes show similar mechanistic properties, notable differences are highlighted in this study. In B. adusta, the AAO oxidase activity is limited by the reoxidation of the flavin, while in P. eryngii the slower step takes place during the reductive half-reaction, which determines the overall reaction rate. By contrast, dehydrogenase activity in both enzymes, irrespective of the alcohol participating in the reaction, is limited by the hydroquinone release from the active site. Despite these differences, both AAOs are more efficient as dehydrogenases, supporting the physiological role of this activity in lignocellulosic decay. This dual activity would allow these enzymes to adapt to different environments based on the available electron acceptors.
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Affiliation(s)
- Ana Serrano
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | - Paula Cinca-Fernando
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, BIFI (GBsC-CSIC Joint Unit), Universidad de Zaragoza, Zaragoza, Spain
| | - Juan Carro
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | - Adrián Velázquez-Campoy
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, BIFI (GBsC-CSIC Joint Unit), Universidad de Zaragoza, Zaragoza, Spain
- Institute for Health Research Aragon (IIS Aragon), Zaragoza, Spain
- Biomedical Research Networking Center in Hepatic and Digestive Diseases (CIBERehd), Madrid, Spain
| | - Marta Martínez-Júlvez
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, BIFI (GBsC-CSIC Joint Unit), Universidad de Zaragoza, Zaragoza, Spain
| | - Ángel T. Martínez
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | - Patricia Ferreira
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, BIFI (GBsC-CSIC Joint Unit), Universidad de Zaragoza, Zaragoza, Spain
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Sánchez-Ruiz MI, Santillana E, Linde D, Romero A, Martínez AT, Ruiz-Dueñas FJ. Structure-function characterization of two enzymes from novel subfamilies of manganese peroxidases secreted by the lignocellulose-degrading Agaricales fungi Agrocybe pediades and Cyathus striatus. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:74. [PMID: 38824538 PMCID: PMC11144326 DOI: 10.1186/s13068-024-02517-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 05/11/2024] [Indexed: 06/03/2024]
Abstract
BACKGROUND Manganese peroxidases (MnPs) are, together with lignin peroxidases and versatile peroxidases, key elements of the enzymatic machineries secreted by white-rot fungi to degrade lignin, thus providing access to cellulose and hemicellulose in plant cell walls. A recent genomic analysis of 52 Agaricomycetes species revealed the existence of novel MnP subfamilies differing in the amino-acid residues that constitute the manganese oxidation site. Following this in silico analysis, a comprehensive structure-function study is needed to understand how these enzymes work and contribute to transform the lignin macromolecule. RESULTS Two MnPs belonging to the subfamilies recently classified as MnP-DGD and MnP-ESD-referred to as Ape-MnP1 and Cst-MnP1, respectively-were identified as the primary peroxidases secreted by the Agaricales species Agrocybe pediades and Cyathus striatus when growing on lignocellulosic substrates. Following heterologous expression and in vitro activation, their biochemical characterization confirmed that these enzymes are active MnPs. However, crystal structure and mutagenesis studies revealed manganese coordination spheres different from those expected after their initial classification. Specifically, a glutamine residue (Gln333) in the C-terminal tail of Ape-MnP1 was found to be involved in manganese binding, along with Asp35 and Asp177, while Cst-MnP1 counts only two amino acids (Glu36 and Asp176), instead of three, to function as a MnP. These findings led to the renaming of these subfamilies as MnP-DDQ and MnP-ED and to re-evaluate their evolutionary origin. Both enzymes were also able to directly oxidize lignin-derived phenolic compounds, as seen for other short MnPs. Importantly, size-exclusion chromatography analyses showed that both enzymes cause changes in polymeric lignin in the presence of manganese, suggesting their relevance in lignocellulose transformation. CONCLUSIONS Understanding the mechanisms used by basidiomycetes to degrade lignin is of particular relevance to comprehend carbon cycle in nature and to design biotechnological tools for the industrial use of plant biomass. Here, we provide the first structure-function characterization of two novel MnP subfamilies present in Agaricales mushrooms, elucidating the main residues involved in catalysis and demonstrating their ability to modify the lignin macromolecule.
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Affiliation(s)
- María Isabel Sánchez-Ruiz
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Elena Santillana
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Dolores Linde
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Antonio Romero
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Angel T Martínez
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
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Tjallinks G, Boverio A, Maric I, Rozeboom H, Arentshorst M, Visser J, Ram AFJ, Mattevi A, Fraaije MW. Structure elucidation and characterization of patulin synthase, insights into the formation of a fungal mycotoxin. FEBS J 2023; 290:5114-5126. [PMID: 37366079 DOI: 10.1111/febs.16804] [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: 02/10/2023] [Revised: 04/06/2023] [Accepted: 04/24/2023] [Indexed: 06/28/2023]
Abstract
Patulin synthase (PatE) from Penicillium expansum is a flavin-dependent enzyme that catalyses the last step in the biosynthesis of the mycotoxin patulin. This secondary metabolite is often present in fruit and fruit-derived products, causing postharvest losses. The patE gene was expressed in Aspergillus niger allowing purification and characterization of PatE. This confirmed that PatE is active not only on the proposed patulin precursor ascladiol but also on several aromatic alcohols including 5-hydroxymethylfurfural. By elucidating its crystal structure, details on its catalytic mechanism were revealed. Several aspects of the active site architecture are reminiscent of that of fungal aryl-alcohol oxidases. Yet, PatE is most efficient with ascladiol as substrate confirming its dedicated role in biosynthesis of patulin.
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Affiliation(s)
- Gwen Tjallinks
- Molecular Enzymology, University of Groningen, The Netherlands
- Department of Biology and Biotechnology, University of Pavia, Italy
| | - Alessandro Boverio
- Molecular Enzymology, University of Groningen, The Netherlands
- Department of Biology and Biotechnology, University of Pavia, Italy
| | - Ivana Maric
- Molecular Enzymology, University of Groningen, The Netherlands
| | | | | | - Jaap Visser
- Institute of Biology Leiden, Leiden University, The Netherlands
| | - Arthur F J Ram
- Institute of Biology Leiden, Leiden University, The Netherlands
| | - Andrea Mattevi
- Department of Biology and Biotechnology, University of Pavia, Italy
| | - Marco W Fraaije
- Molecular Enzymology, University of Groningen, The Netherlands
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Ferreira P, Carro J, Balcells B, Martínez AT, Serrano A. Expanding the Physiological Role of Aryl-Alcohol Flavooxidases as Quinone Reductases. Appl Environ Microbiol 2023; 89:e0184422. [PMID: 37154753 DOI: 10.1128/aem.01844-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023] Open
Abstract
Aryl-alcohol oxidases (AAOs) are members of the glucose-methanol-choline oxidase/dehydrogenase (GMC) superfamily. These extracellular flavoproteins have been described as auxiliary enzymes in the degradation of lignin by several white-rot basidiomycetes. In this context, they oxidize fungal secondary metabolites and lignin-derived compounds using O2 as an electron acceptor, and supply H2O2 to ligninolytic peroxidases. Their substrate specificity, including mechanistic aspects of the oxidation reaction, has been characterized in Pleurotus eryngii AAO, taken as a model enzyme of this GMC superfamily. AAOs show broad reducing-substrate specificity in agreement with their role in lignin degradation, being able to oxidize both nonphenolic and phenolic aryl alcohols (and hydrated aldehydes). In the present work, the AAOs from Pleurotus ostreatus and Bjerkandera adusta were heterologously expressed in Escherichia coli, and their physicochemical properties and oxidizing abilities were compared with those of the well-known recombinant AAO from P. eryngii. In addition, electron acceptors different from O2, such as p-benzoquinone and the artificial redox dye 2,6-Dichlorophenolindophenol, were also studied. Differences in reducing-substrate specificity were found between the AAO enzymes from B. adusta and the two Pleurotus species. Moreover, the three AAOs oxidized aryl alcohols concomitantly with the reduction of p-benzoquinone, with similar or even higher efficiencies than when using their preferred oxidizing-substrate, O2. IMPORTANCE In this work, quinone reductase activity is analyzed in three AAO flavooxidases, whose preferred oxidizing-substrate is O2. The results presented, including reactions in the presence of both oxidizing substrates-benzoquinone and molecular oxygen-suggest that such aryl-alcohol dehydrogenase activity, although less important than its oxidase activity in terms of maximal turnover, may have a physiological role during fungal decay of lignocellulose by the reduction of quinones (and phenoxy radicals) from lignin degradation, preventing repolymerization. Moreover, the resulting hydroquinones would participate in redox-cycling reactions for the production of hydroxyl free radical involved in the oxidative attack of the plant cell-wall. Hydroquinones can also act as mediators for laccases and peroxidases in lignin degradation in the form of semiquinone radicals, as well as activators of lytic polysaccharide monooxygenases in the attack of crystalline cellulose. Moreover, reduction of these, and other phenoxy radicals produced by laccases and peroxidases, promotes lignin degradation by limiting repolymerization reactions. These findings expand the role of AAO in lignin biodegradation.
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Affiliation(s)
- Patricia Ferreira
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, BIFI (GBsC-CSIC Joint Unit), Universidad de Zaragoza, Zaragoza, Spain
| | - Juan Carro
- Centro de Investigaciones Biológicas "Margarita Salas", CSIC, Madrid, Spain
| | - Beatriz Balcells
- Centro de Investigaciones Biológicas "Margarita Salas", CSIC, Madrid, Spain
| | - Angel T Martínez
- Centro de Investigaciones Biológicas "Margarita Salas", CSIC, Madrid, Spain
| | - Ana Serrano
- Centro de Investigaciones Biológicas "Margarita Salas", CSIC, Madrid, Spain
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Wu B, Wang S, Ma Y, Yuan S, Hollmann F, Wang Y. Structure-Based Redesign of a Methanol Oxidase into an "Aryl Alcohol Oxidase" for Enzymatic Synthesis of Aromatic Flavor Compounds. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:6406-6414. [PMID: 37040179 DOI: 10.1021/acs.jafc.3c01069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Alcohol oxidases (AOxs) catalyze the aerobic oxidation of alcohols to the corresponding carbonyl products (aldehydes or ketones), producing only H2O2 as the byproduct. The majority of known AOxs, however, have a strong preference for small, primary alcohols, limiting their broad applicability, e.g., in the food industry. To broaden the product scope of AOxs, we performed structure-guided enzyme engineering of a methanol oxidase from Phanerochaete chrysosporium (PcAOx). The substrate preference was extended from methanol to a broad range of benzylic alcohols by modifying the substrate binding pocket. A mutant (PcAOx-EFMH) with four substitutions exhibited improved catalytic activity toward benzyl alcohols with increased conversion and kcat toward the benzyl alcohol from 11.3 to 88.9% and from 0.5 to 2.6 s-1, respectively. The molecular basis for the change of substrate selectivity was analyzed by molecular simulation.
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Affiliation(s)
- Bin Wu
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Shiyu Wang
- Research Center for Computer-Aided Drug Discovery, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- College of Chemical Science, University of Chinese Academy of Sciences, Beijing 101408, China
| | - Yunjian Ma
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Shuguang Yuan
- Research Center for Computer-Aided Drug Discovery, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Frank Hollmann
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Yonghua Wang
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
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Bienzymatic Cascade Combining a Peroxygenase with an Oxidase for the Synthesis of Aromatic Aldehydes from Benzyl Alcohols. Catalysts 2023. [DOI: 10.3390/catal13010145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Aromatic aldehydes are important aromatic compounds for the flavour and fragrance industry. In this study, a parallel cascade combining aryl alcohol oxidase from Pleurotus eryngii (PeAAOx) and unspecific peroxygenase from the basidiomycete Agrocybe aegerita (AaeUPO) to convert aromatic primary alcohols into high-value aromatic aldehydes is proposed. Key influencing factors in the process of enzyme cascade catalysis, such as enzyme dosage, pH and temperature, were investigated. The universality of PeAAOx coupled with AaeUPO cascade catalysis for the synthesis of aromatic aldehyde flavour compounds from aromatic primary alcohols was evaluated. In a partially optimised system (comprising 30 μM PeAAOx, 2 μM AaeUPO at pH 7 and 40 °C) up to 84% conversion of 50 mM veratryl alcohol into veratryl aldehyde was achieved in a self-sufficient aerobic reaction. Promising turnover numbers of 2800 and 21,000 for PeAAOx and AaeUPO, respectively, point towards practical applicability.
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Properties, Physiological Functions and Involvement of Basidiomycetous Alcohol Oxidase in Wood Degradation. Int J Mol Sci 2022; 23:ijms232213808. [PMID: 36430286 PMCID: PMC9699415 DOI: 10.3390/ijms232213808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/04/2022] [Accepted: 11/06/2022] [Indexed: 11/11/2022] Open
Abstract
Extensive research efforts have been devoted to describing yeast alcohol oxidase (AO) and its promoter region, which is vastly applied in studies of heterologous gene expression. However, little is known about basidiomycetous AO and its physiological role in wood degradation. This review describes several alcohol oxidases from both white and brown rot fungi, highlighting their physicochemical and kinetic properties. Moreover, the review presents a detailed analysis of available AO-encoding gene promoter regions in basidiomycetous fungi with a discussion of the manipulations of culture conditions in relation to the modification of alcohol oxidase gene expression and changes in enzyme production. The analysis of reactions catalyzed by lignin-modifying enzymes (LME) and certain lignin auxiliary enzymes (LDA) elucidated the possible involvement of alcohol oxidase in the degradation of derivatives of this polymer. Combined data on lignin degradation pathways suggest that basidiomycetous AO is important in secondary reactions during lignin decomposition by wood degrading fungi. With numerous alcoholic substrates, the enzyme is probably engaged in a variety of catalytic reactions leading to the detoxification of compounds produced in lignin degradation processes and their utilization as a carbon source by fungal mycelium.
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Romero‐Fernandez M, Heckmann CM, Paradisi F. Biocatalytic Production of a Nylon 6 Precursor from Caprolactone in Continuous Flow. CHEMSUSCHEM 2022; 15:e202200811. [PMID: 35671069 PMCID: PMC9546309 DOI: 10.1002/cssc.202200811] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/03/2022] [Indexed: 06/07/2023]
Abstract
6-Aminocaproic acid (6ACA) is a key building block and an attractive precursor of caprolactam, which is used to synthesize nylon 6, one of the most common polymers manufactured nowadays. (Bio)-production of platform chemicals from renewable feedstocks is instrumental to tackle climate change and decrease fossil fuel dependence. Here, the cell-free biosynthesis of 6ACA from 6-hydroxycaproic acid was achieved using a co-immobilized multienzyme system based on horse liver alcohol dehydrogenase, Halomonas elongata transaminase, and Lactobacillus pentosus NADH oxidase for in-situ cofactor recycling, with >90 % molar conversion (m.c.) The integration of a step to synthesize hydroxy-acid from lactone by immobilized Candida antarctica lipase B resulted in >80 % m.c. of ϵ-caprolactone to 6ACA, >20 % of δ-valerolactone to 5-aminovaleric acid, and 30 % of γ-butyrolactone to γ-aminobutyric acid in one-pot batch reactions. Two serial packed-bed reactors were set up using these biocatalysts and applied to the continuous-flow synthesis of 6ACA from ϵ-caprolactone, achieving a space-time yield of up to 3.31 g6ACA h-1 L-1 with a segmented liquid/air flow for constant oxygen supply.
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Affiliation(s)
- Maria Romero‐Fernandez
- School of ChemistryUniversity of NottinghamUniversity ParkNG7 2RDNottinghamUnited Kingdom
| | - Christian M. Heckmann
- School of ChemistryUniversity of NottinghamUniversity ParkNG7 2RDNottinghamUnited Kingdom
| | - Francesca Paradisi
- School of ChemistryUniversity of NottinghamUniversity ParkNG7 2RDNottinghamUnited Kingdom
- Department of ChemistryBiochemistry and Pharmaceutical SciencesUniversity of BernFreiestrasse 33012BernSwitzerland
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Jankowski N, Koschorreck K, Urlacher VB. Aryl‐Alcohol‐Oxidase‐Mediated Synthesis of Piperonal and Other Valuable Aldehydes. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202200381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nina Jankowski
- Institute of Biochemistry Heinrich-Heine University Düsseldorf Universitätsstraße 1 40225 Düsseldorf Germany
| | - Katja Koschorreck
- Institute of Biochemistry Heinrich-Heine University Düsseldorf Universitätsstraße 1 40225 Düsseldorf Germany
| | - Vlada B. Urlacher
- Institute of Biochemistry Heinrich-Heine University Düsseldorf Universitätsstraße 1 40225 Düsseldorf Germany
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Lappe A, Jankowski N, Albrecht A, Koschorreck K. Characterization of a thermotolerant aryl-alcohol oxidase from Moesziomyces antarcticus oxidizing 5-hydroxymethyl-2-furancarboxylic acid. Appl Microbiol Biotechnol 2021; 105:8313-8327. [PMID: 34643786 PMCID: PMC8557139 DOI: 10.1007/s00253-021-11557-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/23/2021] [Accepted: 08/26/2021] [Indexed: 12/01/2022]
Abstract
The development of enzymatic processes for the environmentally friendly production of 2,5-furandicarboxylic acid (FDCA), a renewable precursor for bioplastics, from 5-hydroxymethylfurfural (HMF) has gained increasing attention over the last years. Aryl-alcohol oxidases (AAOs) catalyze the oxidation of HMF to 5-formyl-2-furancarboxylic acid (FFCA) through 2,5-diformylfuran (DFF) and have thus been applied in enzymatic reaction cascades for the production of FDCA. AAOs are flavoproteins that oxidize a broad range of benzylic and aliphatic allylic primary alcohols to the corresponding aldehydes, and in some cases further to acids, while reducing molecular oxygen to hydrogen peroxide. These promising biocatalysts can also be used for the synthesis of flavors, fragrances, and chemical building blocks, but their industrial applicability suffers from low production yield in natural and heterologous hosts. Here we report on heterologous expression of a new aryl-alcohol oxidase, MaAAO, from Moesziomyces antarcticus at high yields in the methylotrophic yeast Pichia pastoris (recently reclassified as Komagataella phaffii). Fed-batch fermentation of recombinant P. pastoris yielded around 750 mg of active enzyme per liter of culture. Purified MaAAO was highly stable at pH 2-9 and exhibited high thermal stability with almost 95% residual activity after 48 h at 57.5 °C. MaAAO accepts a broad range of benzylic primary alcohols, aliphatic allylic alcohols, and furan derivatives like HMF as substrates and some oxidation products thereof like piperonal or perillaldehyde serve as building blocks for pharmaceuticals or show health-promoting effects. Besides this, MaAAO oxidized 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) to FFCA, which has not been shown for any other AAO so far. Combining MaAAO with an unspecific peroxygenase oxidizing HMFCA to FFCA in one pot resulted in complete conversion of HMF to FDCA within 144 h. MaAAO is thus a promising biocatalyst for the production of precursors for bioplastics and bioactive compounds. KEY POINTS: • MaAAO from M. antarcticus was expressed in P. pastoris at 750 mg/l. • MaAAO oxidized 5-hydroxymethyl-2-furancarboxylic acid (HMFCA). • Complete conversion of HMF to 2,5-furandicarboxylic acid by combining MaAAO and UPO.
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Affiliation(s)
- Alessa Lappe
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Nina Jankowski
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Annemie Albrecht
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Katja Koschorreck
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany.
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11
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Jankowski N, Urlacher VB, Koschorreck K. Two adjacent C-terminal mutations enable expression of aryl-alcohol oxidase from Pleurotus eryngii in Pichia pastoris. Appl Microbiol Biotechnol 2021; 105:7743-7755. [PMID: 34545417 PMCID: PMC8502153 DOI: 10.1007/s00253-021-11585-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/23/2021] [Accepted: 08/26/2021] [Indexed: 10/30/2022]
Abstract
Fungal aryl-alcohol oxidases (AAOs) are attractive biocatalysts because they selectively oxidize a broad range of aromatic and aliphatic allylic primary alcohols while yielding hydrogen peroxide as the only by-product. However, their use is hampered by challenging and often unsuccessful heterologous expression. Production of PeAAO1 from Pleurotus eryngii ATCC 90787 in Pichia pastoris failed, while PeAAO2 from P. eryngii P34 with an amino acid identity of 99% was expressed at high yields. By successively introducing mutations in PeAAO1 to mimic the sequence of PeAAO2, the double mutant PeAAO1 ER with mutations K583E and Q584R was constructed, that was successfully expressed in P. pastoris. Functional expression was enhanced up to 155 U/l via further replacements D361N (variant NER) or V367A (variant AER). Fed-batch cultivation of recombinant P. pastoris yielded up to 116 mg/l of active variants. Glycosylated PeAAO1 variants demonstrated high stability and catalytic efficiencies similar to PeAAO2. Interestingly, P. pastoris expressing PeAAO1 variant ER contained roughly 13 gene copies but showed similar volumetric activity as NER and AER with one to two gene copies and four times lower mRNA levels. Additional H-bonds and salt bridges introduced by mutations K583E and Q584R might facilitate heterologous expression by enhanced protein folding.Key points• PeAAO1 not expressed in P. pastoris and PeAAO2 well-expressed in Pichia differ at 7 positions.• Expression of PeAAO1 in P. pastoris achieved through mutagenesis based on PeAAO2 sequence.• Combination of K583E and Q584R is essential for expression of PeAAO1 in P. pastoris.
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Affiliation(s)
- Nina Jankowski
- Institute of Biochemistry, Heinrich-Heine-University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Vlada B Urlacher
- Institute of Biochemistry, Heinrich-Heine-University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Katja Koschorreck
- Institute of Biochemistry, Heinrich-Heine-University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany.
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Agaricales Mushroom Lignin Peroxidase: From Structure-Function to Degradative Capabilities. Antioxidants (Basel) 2021; 10:antiox10091446. [PMID: 34573078 PMCID: PMC8472802 DOI: 10.3390/antiox10091446] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 11/29/2022] Open
Abstract
Lignin biodegradation has been extensively studied in white-rot fungi, which largely belong to order Polyporales. Among the enzymes that wood-rotting polypores secrete, lignin peroxidases (LiPs) have been labeled as the most efficient. Here, we characterize a similar enzyme (ApeLiP) from a fungus of the order Agaricales (with ~13,000 described species), the soil-inhabiting mushroom Agrocybe pediades. X-ray crystallography revealed that ApeLiP is structurally related to Polyporales LiPs, with a conserved heme-pocket and a solvent-exposed tryptophan. Its biochemical characterization shows that ApeLiP can oxidize both phenolic and non-phenolic lignin model-compounds, as well as different dyes. Moreover, using stopped-flow rapid spectrophotometry and 2D-NMR, we demonstrate that ApeLiP can also act on real lignin. Characterization of a variant lacking the above tryptophan residue shows that this is the oxidation site for lignin and other high redox-potential substrates, and also plays a role in phenolic substrate oxidation. The reduction potentials of the catalytic-cycle intermediates were estimated by stopped-flow in equilibrium reactions, showing similar activation by H2O2, but a lower potential for the rate-limiting step (compound-II reduction) compared to other LiPs. Unexpectedly, ApeLiP was stable from acidic to basic pH, a relevant feature for application considering its different optima for oxidation of phenolic and nonphenolic compounds.
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Sánchez-Ruiz MI, Martínez AT, Serrano A. Optimizing operational parameters for the enzymatic production of furandicarboxylic acid building block. Microb Cell Fact 2021; 20:180. [PMID: 34503517 PMCID: PMC8427864 DOI: 10.1186/s12934-021-01669-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 08/25/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND 2,5-Furandicarboxylic acid (FDCA) is a precursor for green plastics due to its structural similarity to terephthalic acid, a common precursor of oil-derived polymers, and its potential production from sugars obtained from plant biomass. Hydroxymethylfurfural oxidase (HMFO) has been reported as a promising biocatalyst for FDCA production since it can convert bio-based 5-hydroxymethylfurfural (HMF) into FDCA building block. This three-step oxidation reaction occurs through the diformylfuran and 2,5-formylfurancarboxylic acid (FFCA) intermediates. Several efforts have been made for the development of HMFO variants that increase FDCA yields by improving their activities over the reaction intermediates. However, there is still limited insight into how operational conditions can influence these enzymatic reactions. The setup of optimal reaction conditions would enable to understand potential problems hampering the effective industrial production of this bioplastic precursor using HMFO as biocatalyst. RESULTS In this work, several parameters affecting the performance of Methylovorus sp HMFO oxidizing HMF have been analyzed for the wild-type enzyme, and its V367R and W466F single variants, V367R/W466F double variant, and I73V/H74Y/G356H/V367R/T414K/A419Y/A435E/W466F (8BxHMFO) octuple variant. Our results show how the oxidation of HMF by HMFO enzymes is highly influenced by pH, with different optimal pH values for the different improved variants. Moreover, the enzymes are not stable at high hydrogen peroxide concentrations and their activity is inhibited by the FFCA intermediate in a pH-dependent way. These limitations can be efficiently overcome with the addition of catalase to the reaction medium, which removes the hydrogen peroxide formed during the oxidations, and the controlled dosage of the substrate to limit the amount of FFCA accumulated in the reaction. The different behavior of wild-type HMFO and its variants against pH, hydrogen peroxide and FFCA highlights the importance of considering each variant as an individual enzyme with its own operational conditions for an eventual industrial FDCA production. CONCLUSIONS This work provides information of those parameters that condition a high production of FDCA by HMFO. Unraveling these factors allowed to increase the FDCA yields by using the most stable enzymes at their optimal pH for HMF oxidation, removing the peroxide with catalase, and avoiding FFCA accumulation by controlling substrate and/or enzyme concentration. These above findings will be useful when planning a future scale-up of these conversions and will provide new viewpoints for the design of HMFO variants that render a more effective performance during HMF conversion into FDCA.
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Affiliation(s)
- María Isabel Sánchez-Ruiz
- Centro de Investigaciones Biológicas "Margarita Salas" (CIB), CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Angel T Martínez
- Centro de Investigaciones Biológicas "Margarita Salas" (CIB), CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
| | - Ana Serrano
- Centro de Investigaciones Biológicas "Margarita Salas" (CIB), CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
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Pecularities and applications of aryl-alcohol oxidases from fungi. Appl Microbiol Biotechnol 2021; 105:4111-4126. [PMID: 33997930 PMCID: PMC8140971 DOI: 10.1007/s00253-021-11337-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/03/2021] [Accepted: 05/06/2021] [Indexed: 12/16/2022]
Abstract
Abstract Aryl-alcohol oxidases (AAOs) are FAD-containing enzymes that oxidize a broad range of aromatic as well as aliphatic allylic alcohols to aldehydes. Their broad substrate spectrum accompanied by the only need for molecular oxygen as cosubstrate and production of hydrogen peroxide as sole by-product makes these enzymes very promising biocatalysts. AAOs were used in the synthesis of flavors, fragrances, and other high-value-added compounds and building blocks as well as in dye decolorization and pulp biobleaching. Furthermore, AAOs offer a huge potential as efficient suppliers of hydrogen peroxide for peroxidase- and peroxygenase-catalyzed reactions. A prerequisite for application as biocatalysts at larger scale is the production of AAOs in sufficient amounts. Heterologous expression of these predominantly fungal enzymes is, however, quite challenging. This review summarizes different approaches aiming at enhancing heterologous expression of AAOs and gives an update on substrates accepted by these promising enzymes as well as potential fields of their application. Key points • Aryl-alcohol oxidases (AAOs) supply ligninolytic peroxidases with H2O2. • AAOs accept a broad spectrum of aromatic and aliphatic allylic alcohols. • AAOs are potential biocatalysts for the production of high-value-added bio-based chemicals.
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Gomez de Santos P, Lazaro S, Viña-Gonzalez J, Hoang MD, Sánchez-Moreno I, Glieder A, Hollmann F, Alcalde M. Evolved Peroxygenase–Aryl Alcohol Oxidase Fusions for Self-Sufficient Oxyfunctionalization Reactions. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03029] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
| | - Sofia Lazaro
- Department of Biocatalysis, Institute of Catalysis, CSIC, 28049 Madrid, Spain
| | - Javier Viña-Gonzalez
- Department of Biocatalysis, Institute of Catalysis, CSIC, 28049 Madrid, Spain
- EvoEnzyme S.L., Marie Curie 2, 28049 Madrid, Spain
| | - Manh Dat Hoang
- Department of Biocatalysis, Institute of Catalysis, CSIC, 28049 Madrid, Spain
- Institute of Biochemical Engineering, Technical University of Munich, Boltzmannstr. 15, 85748 Garching, Germany
| | | | - Anton Glieder
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
- Bisy e.U., Wuenschendorf 292, 8200 Hofstaetten a. d. Raab, Austria
| | - Frank Hollmann
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Miguel Alcalde
- Department of Biocatalysis, Institute of Catalysis, CSIC, 28049 Madrid, Spain
- EvoEnzyme S.L., Marie Curie 2, 28049 Madrid, Spain
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Liu E, Wilkins MR. Process optimization and scale-up production of fungal aryl alcohol oxidase from genetically modified Aspergillus nidulans in stirred-tank bioreactor. BIORESOURCE TECHNOLOGY 2020; 315:123792. [PMID: 32659422 DOI: 10.1016/j.biortech.2020.123792] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
Microbial production of aryl alcohol oxidase (AAO) has attracted increasing attention due to the central role of AAO in enzymatic lignin depolymerization. However, large-scale production of AAO has not been reached because of the low yield and inefficient fermentation process. This study aims to optimize the process parameters and scale-up production of AAO using Aspergillus nidulans in a stirred-tank bioreactor. Effects of pH and dissolved oxygen on AAO production at bioreactor scale were particularly investigated. Results revealed that pH control significantly affected protein production and increasing dissolved oxygen level stimulated AAO production. The greatest AAO activity (1906 U/L) and protein concentration (1.19 g/L) were achieved in 48 h at 60% dissolved oxygen with pH controlled at 6.0. The yield and productivity (in 48 h) were 31.2 U/g maltose and 39.7 U/L/h, respectively. In addition, crude AAO was concentrated and partially purified by ultrafiltration and verified by protein identification.
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Affiliation(s)
- Enshi Liu
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Mark R Wilkins
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, USA; Industrial Agricultural Products Center, University of Nebraska-Lincoln, Lincoln, NE 68583, USA; Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
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High-level expression of aryl-alcohol oxidase 2 from Pleurotus eryngii in Pichia pastoris for production of fragrances and bioactive precursors. Appl Microbiol Biotechnol 2020; 104:9205-9218. [PMID: 32949280 PMCID: PMC7567689 DOI: 10.1007/s00253-020-10878-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/14/2020] [Accepted: 09/02/2020] [Indexed: 12/13/2022]
Abstract
Abstract The fungal secretome comprises various oxidative enzymes participating in the degradation of lignocellulosic biomass as a central step in carbon recycling. Among the secreted enzymes, aryl-alcohol oxidases (AAOs) are of interest for biotechnological applications including production of bio-based precursors for plastics, bioactive compounds, and flavors and fragrances. Aryl-alcohol oxidase 2 (PeAAO2) from the fungus Pleurotus eryngii was heterologously expressed and secreted at one of the highest yields reported so far of 315 mg/l using the methylotrophic yeast Pichia pastoris (recently reclassified as Komagataella phaffii). The glycosylated PeAAO2 exhibited a high stability in a broad pH range between pH 3.0 and 9.0 and high thermal stability up to 55 °C. Substrate screening with 41 compounds revealed that PeAAO2 oxidized typical AAO substrates like p-anisyl alcohol, veratryl alcohol, and trans,trans-2,4-hexadienol with up to 8-fold higher activity than benzyl alcohol. Several compounds not yet reported as substrates for AAOs were oxidized by PeAAO2 as well. Among them, cumic alcohol and piperonyl alcohol were oxidized to cuminaldehyde and piperonal with high catalytic efficiencies of 84.1 and 600.2 mM−1 s−1, respectively. While the fragrance and flavor compound piperonal also serves as starting material for agrochemical and pharmaceutical building blocks, various positive health effects have been attributed to cuminaldehyde including anticancer, antidiabetic, and neuroprotective effects. PeAAO2 is thus a promising biocatalyst for biotechnological applications. Key points • Aryl-alcohol oxidase PeAAO2 from P. eryngii was produced in P. pastoris at 315 mg/l. • Purified enzyme exhibited stability over a broad pH and temperature range. • Oxidation products cuminaldehyde and piperonal are of biotechnological interest. Graphical abstract![]() Electronic supplementary material The online version of this article (10.1007/s00253-020-10878-4) contains supplementary material, which is available to authorized users.
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Abstract
Aryl-alcohol oxidases (AAO) constitute a family of FAD-containing enzymes, included in the glucose-methanol-choline oxidase/dehydrogenase superfamily of proteins. They are commonly found in fungi, where their eco-physiological role is to produce hydrogen peroxide that activates ligninolytic peroxidases in white-rot (lignin-degrading) basidiomycetes or to trigger the Fenton reactions in brown-rot (carbohydrate-degrading) basidiomycetes. These enzymes catalyze the oxidation of a plethora of aromatic, and some aliphatic, polyunsaturated alcohols bearing conjugated primary hydroxyl group. Besides, the enzymes show activity on the hydrated forms of the corresponding aldehydes. Some AAO features, such as the broad range of substrates that it can oxidize (with the only need of molecular oxygen as co-substrate) and its stereoselective mechanism, confer good properties to these enzymes as industrial biocatalysts. In fact, AAO can be used for different biotechnological applications, such as flavor synthesis, secondary alcohol deracemization and oxidation of furfurals for the production of furandicarboxylic acid as a chemical building block. Also, AAO can participate in processes of interest in the wood biorefinery and textile industries as an auxiliary enzyme providing hydrogen peroxide to ligninolytic or dye-decolorizing peroxidases. Both rational design and directed molecular evolution have been employed to engineer AAO for some of the above biotechnological applications.
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Affiliation(s)
- Ana Serrano
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Madrid, Spain.
| | - Juan Carro
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Madrid, Spain
| | - Angel T Martínez
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Madrid, Spain.
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Kadowaki MAS, Higasi PMR, de Godoy MO, de Araújo EA, Godoy AS, Prade RA, Polikarpov I. Enzymatic versatility and thermostability of a new aryl-alcohol oxidase from Thermothelomyces thermophilus M77. Biochim Biophys Acta Gen Subj 2020; 1864:129681. [PMID: 32653619 DOI: 10.1016/j.bbagen.2020.129681] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/14/2020] [Accepted: 06/30/2020] [Indexed: 01/23/2023]
Abstract
Background Fungal aryl-alcohol oxidases (AAOx) are extracellular flavoenzymes that belong to glucose-methanol-choline oxidoreductase family and are responsible for the selective conversion of primary aromatic alcohols into aldehydes and aromatic aldehydes to their corresponding acids, with concomitant production of hydrogen peroxide (H2O2) as by-product. The H2O2 can be provided to lignin degradation pathway, a biotechnological property explored in biofuel production. In the thermophilic fungus Thermothelomyces thermophilus (formerly Myceliophthora thermophila), just one AAOx was identified in the exo-proteome. Methods The glycosylated and non-refolded crystal structure of an AAOx from T. thermophilus at 2.6 Å resolution was elucidated by X-ray crystallography combined with small-angle X-ray scattering (SAXS) studies. Moreover, biochemical analyses were carried out to shed light on enzyme substrate specificity and thermostability. Results This flavoenzyme harbors a flavin adenine dinucleotide as a cofactor and is able to oxidize aromatic substrates and 5-HMF. Our results also show that the enzyme has similar oxidation rates for bulky or simple aromatic substrates such as cinnamyl and veratryl alcohols. Moreover, the crystal structure of MtAAOx reveals an open active site, which might explain observed specificity of the enzyme. Conclusions MtAAOx shows previously undescribed structural differences such as a fully accessible catalytic tunnel, heavy glycosylation and Ca2+ binding site providing evidences for thermostability and activity of the enzymes from AA3_2 subfamily. General significance Structural and biochemical analyses of MtAAOx could be important for comprehension of aryl-alcohol oxidases structure-function relationships and provide additional molecular tools to be used in future biotechnological applications.
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Affiliation(s)
- Marco Antonio Seiki Kadowaki
- São Carlos Institute of Physics, University of São Paulo, Av. Trabalhador São-carlense, 400, São Carlos, SP 13566-590, Brazil.
| | - Paula Miwa Rabelo Higasi
- São Carlos Institute of Physics, University of São Paulo, Av. Trabalhador São-carlense, 400, São Carlos, SP 13566-590, Brazil
| | - Mariana Ortiz de Godoy
- São Carlos Institute of Physics, University of São Paulo, Av. Trabalhador São-carlense, 400, São Carlos, SP 13566-590, Brazil
| | - Evandro Ares de Araújo
- São Carlos Institute of Physics, University of São Paulo, Av. Trabalhador São-carlense, 400, São Carlos, SP 13566-590, Brazil
| | - Andre Schutzer Godoy
- São Carlos Institute of Physics, University of São Paulo, Av. Trabalhador São-carlense, 400, São Carlos, SP 13566-590, Brazil
| | - Rolf Alexander Prade
- Departments of Microbiology & Molecular Genetics and Biochemistry & Molecular Biology, Oklahoma State University, OK, USA
| | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, Av. Trabalhador São-carlense, 400, São Carlos, SP 13566-590, Brazil.
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Viña-Gonzalez J, Alcalde M. Directed evolution of the aryl-alcohol oxidase: Beyond the lab bench. Comput Struct Biotechnol J 2020; 18:1800-1810. [PMID: 32695272 PMCID: PMC7358221 DOI: 10.1016/j.csbj.2020.06.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/19/2020] [Accepted: 06/20/2020] [Indexed: 11/22/2022] Open
Abstract
Aryl-alcohol oxidase (AAO) is a fungal GMC flavoprotein secreted by white-rot fungi that supplies H2O2 to the ligninolytic consortium. This enzyme can oxidize a wide array of aromatic alcohols in a highly enantioselective manner, an important trait in organic synthesis. The best strategy to adapt AAO to industrial needs is to engineer its properties by directed evolution, aided by computational analysis. The aim of this review is to describe the strategies and challenges we faced when undertaking laboratory evolution of AAO. After a comprehensive introduction into the structure of AAO, its function and potential applications, the different directed evolution enterprises designed to express the enzyme in an active and soluble form in yeast are described, as well as those to unlock new activities involving the oxidation of secondary aromatic alcohols and the synthesis of furandicarboxylic acids.
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Affiliation(s)
- Javier Viña-Gonzalez
- Department of Biocatalysis, Institute of Catalysis, CSIC, Cantoblanco, 28049 Madrid, Spain
| | - Miguel Alcalde
- Department of Biocatalysis, Institute of Catalysis, CSIC, Cantoblanco, 28049 Madrid, Spain
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21
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Viña-Gonzalez J, Martinez AT, Guallar V, Alcalde M. Sequential oxidation of 5-hydroxymethylfurfural to furan-2,5-dicarboxylic acid by an evolved aryl-alcohol oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1868:140293. [PMID: 31676448 DOI: 10.1016/j.bbapap.2019.140293] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/09/2019] [Accepted: 10/10/2019] [Indexed: 02/08/2023]
Abstract
Furan-2,5-dicarboxylic acid (FDCA) is a building block of biodegradable plastics that can be used to replace those derived from fossil carbon sources. In recent years, much interest has focused on the synthesis of FDCA from the bio-based 5-hydroxymethylfurfural (HMF) through a cascade of enzyme reactions. Aryl-alcohol oxidase (AAO) and 5-hydroxymethylfurfural oxidase (HMFO) are glucose-methanol-choline flavoenzymes that may be used to produce FDCA from HMF through three sequential oxidations, and without the assistance of auxiliary enzymes. Such a challenging process is dependent on the degree of hydration of the original aldehyde groups and of those formed, the rate-limiting step lying in the final oxidation of the intermediate 5-formyl-furancarboxylic acid (FFCA) to FDCA. While HMFO accepts FFCA as a final substrate in the HMF reaction pathway, AAO is virtually incapable of oxidizing it. Here, we have engineered AAO to perform the stepwise oxidation of HMF to FDCA through its structural alignment with HMFO and directed evolution. With a 3-fold enhanced catalytic efficiency for HMF and a 6-fold improvement in overall conversion, this evolved AAO is a promising point of departure for further engineering aimed at generating an efficient biocatalyst to synthesize FDCA from HMF.
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Affiliation(s)
- Javier Viña-Gonzalez
- Department of Biocatalysis, Institute of Catalysis, CSIC, Cantoblanco, 28049 Madrid, Spain
| | - Angel T Martinez
- Biological Research Center, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Victor Guallar
- Barcelona Supercomputing Center, Jordi Girona 31, 08034 Barcelona, Spain; ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Miguel Alcalde
- Department of Biocatalysis, Institute of Catalysis, CSIC, Cantoblanco, 28049 Madrid, Spain.
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Serrano A, Calviño E, Carro J, Sánchez-Ruiz MI, Cañada FJ, Martínez AT. Complete oxidation of hydroxymethylfurfural to furandicarboxylic acid by aryl-alcohol oxidase. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:217. [PMID: 31528205 PMCID: PMC6737615 DOI: 10.1186/s13068-019-1555-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/31/2019] [Indexed: 05/25/2023]
Abstract
BACKGROUND 5-Hydroxymethylfurfural (HMF) is a highly valuable platform chemical that can be obtained from plant biomass carbohydrates. HMF can be oxidized to 2,5-furandicarboxylic acid (FDCA), which is used as a renewable substitute for the petroleum-based terephthalic acid in polymer production. RESULTS Aryl-alcohol oxidase (AAO) from the white-rot fungus Pleurotus eryngii is able to oxidize HMF and its derivative 2,5-diformylfuran (DFF) producing formylfurancarboxylic acid (FFCA) thanks to its activity on benzylic alcohols and hydrated aldehydes. Here, we report the ability of AAO to produce FDCA from FFCA, opening up the possibility of full oxidation of HMF by this model enzyme. During HMF reactions, an inhibitory effect of the H2O2 produced in the first two oxidation steps was found to be the cause of the lack of AAO activity on FFCA. In situ monitoring of the whole reaction by 1H-NMR confirmed the absence of any unstable dead-end products, undetected in the HPLC analyses, that could be responsible for the incomplete conversion. The deleterious effect of H2O2 was confirmed by successful HMF conversion into FDCA when the AAO reaction was carried out in the presence of catalase. On the other hand, no H2O2 formation was detected during the slow FFCA conversion by AAO in the absence of catalase, in contrast to typical oxidase reaction with HMF and DFF, suggesting an alternative mechanism as reported in some reactions of related flavo-oxidases. Moreover, several active-site AAO variants that yield nearly complete conversion in shorter reaction times than the wild-type enzyme have been identified. CONCLUSIONS The use of catalase to remove H2O2 from the reaction mixture leads to 99% conversion of HMF into FDCA by AAO and several improved variants, although the mechanism of peroxide inhibition of the AAO action on the aldehyde group of FFCA is not fully understood.
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Affiliation(s)
- Ana Serrano
- Biotechnology for Lignocellulosic Biomass, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Eva Calviño
- NMR and Molecular Recognition, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Juan Carro
- Biotechnology for Lignocellulosic Biomass, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - María I. Sánchez-Ruiz
- Biotechnology for Lignocellulosic Biomass, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - F. Javier Cañada
- NMR and Molecular Recognition, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Angel T. Martínez
- Biotechnology for Lignocellulosic Biomass, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
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23
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Viña‐Gonzalez J, Jimenez‐Lalana D, Sancho F, Serrano A, Martinez AT, Guallar V, Alcalde M. Structure‐Guided Evolution of Aryl Alcohol Oxidase from
Pleurotus eryngii
for the Selective Oxidation of Secondary Benzyl Alcohols. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900134] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Javier Viña‐Gonzalez
- Department of Biocatalysis, Institute of CatalysisCSIC, Cantoblanco 28049 Madrid Spain Fax: (+31)-91 5854760; phone: (+34)-91 5854806
| | - Diego Jimenez‐Lalana
- Department of Biocatalysis, Institute of CatalysisCSIC, Cantoblanco 28049 Madrid Spain Fax: (+31)-91 5854760; phone: (+34)-91 5854806
| | - Ferran Sancho
- Barcelona Supercomputing Center Jordi Girona 31 08034 Barcelona Spain
| | - Ana Serrano
- Biological Research CenterCSIC Ramiro de Maeztu 9 28040 Madrid Spain
| | - Angel T. Martinez
- Biological Research CenterCSIC Ramiro de Maeztu 9 28040 Madrid Spain
| | - Victor Guallar
- Barcelona Supercomputing Center Jordi Girona 31 08034 Barcelona Spain
- ICREA Passeig Lluís Companys 23 08010 Barcelona Spain
| | - Miguel Alcalde
- Department of Biocatalysis, Institute of CatalysisCSIC, Cantoblanco 28049 Madrid Spain Fax: (+31)-91 5854760; phone: (+34)-91 5854806
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de Almeida TP, van Schie MMCH, Ma A, Tieves F, Younes SHH, Fernández-Fueyo E, Arends IWCE, Riul A, Hollmann F. Efficient Aerobic Oxidation of trans
-2-Hexen-1-ol using the Aryl Alcohol Oxidase from Pleurotus eryngii. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201801312] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- T. P. de Almeida
- Department of Biotechnology; Delft University of Technology, The; Netherlands
| | | | - A. Ma
- Department of Biotechnology; Delft University of Technology, The; Netherlands
| | - F. Tieves
- Department of Biotechnology; Delft University of Technology, The; Netherlands
| | - S. H. H. Younes
- Department of Biotechnology; Delft University of Technology, The; Netherlands
- Department of Chemistry, Faculty of Science; Sohag University; Sohag 82524 Egypt
| | - E. Fernández-Fueyo
- Department of Biotechnology; Delft University of Technology, The; Netherlands
| | | | - A. Riul
- Department of Applied Physics, “Gleb Wataghin” Institute of Physics (IFGW); University of Campinas (UNICAMP), SP; Brazil
| | - F. Hollmann
- Department of Biotechnology; Delft University of Technology, The; Netherlands
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25
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Serrano A, Sancho F, Viña-González J, Carro J, Alcalde M, Guallar V, Martínez AT. Switching the substrate preference of fungal aryl-alcohol oxidase: towards stereoselective oxidation of secondary benzyl alcohols. Catal Sci Technol 2019. [DOI: 10.1039/c8cy02447b] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Using PELE computational simulations the ability to deracemize secondary benzylic alcohols was introduced (by I500M/F501W double mutation) in stereoselective AAO.
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Affiliation(s)
- Ana Serrano
- Centro de Investigaciones Biológicas
- CSIC
- E-28040 Madrid
- Spain
| | - Ferran Sancho
- Barcelona Supercomputing Center
- E-08034 Barcelona
- Spain
| | | | - Juan Carro
- Centro de Investigaciones Biológicas
- CSIC
- E-28040 Madrid
- Spain
| | - Miguel Alcalde
- Department of Biocatalysis
- Institute of Catalysis
- CSIC
- Madrid
- Spain
| | - Victor Guallar
- Barcelona Supercomputing Center
- E-08034 Barcelona
- Spain
- ICREA
- Barcelona
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Carro J, Amengual-Rigo P, Sancho F, Medina M, Guallar V, Ferreira P, Martínez AT. Multiple implications of an active site phenylalanine in the catalysis of aryl-alcohol oxidase. Sci Rep 2018; 8:8121. [PMID: 29802285 PMCID: PMC5970180 DOI: 10.1038/s41598-018-26445-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/11/2018] [Indexed: 01/15/2023] Open
Abstract
Aryl-alcohol oxidase (AAO) has demonstrated to be an enzyme with a bright future ahead due to its biotechnological potential in deracemisation of chiral compounds, production of bioplastic precursors and other reactions of interest. Expanding our understanding on the AAO reaction mechanisms, through the investigation of its structure-function relationships, is crucial for its exploitation as an industrial biocatalyst. In this regard, previous computational studies suggested an active role for AAO Phe397 at the active-site entrance. This residue is located in a loop that partially covers the access to the cofactor forming a bottleneck together with two other aromatic residues. Kinetic and affinity spectroscopic studies, complemented with computational simulations using the recently developed adaptive-PELE technology, reveal that the Phe397 residue is important for product release and to help the substrates attain a catalytically relevant position within the active-site cavity. Moreover, removal of aromaticity at the 397 position impairs the oxygen-reduction activity of the enzyme. Experimental and computational findings agree very well in the timing of product release from AAO, and the simulations help to understand the experimental results. This highlights the potential of adaptive-PELE to provide answers to the questions raised by the empirical results in the study of enzyme mechanisms.
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Affiliation(s)
- Juan Carro
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040, Madrid, Spain
| | - Pep Amengual-Rigo
- Barcelona Supercomputing Center, Jordi Girona 31, E-08034, Barcelona, Spain
| | - Ferran Sancho
- Barcelona Supercomputing Center, Jordi Girona 31, E-08034, Barcelona, Spain
| | - Milagros Medina
- Department of Biochemistry and Cellular and Molecular Biology, and BIFI, University of Zaragoza, E-50009, Zaragoza, Spain
| | - Victor Guallar
- Barcelona Supercomputing Center, Jordi Girona 31, E-08034, Barcelona, Spain. .,ICREA, Passeig Lluís Companys 23, E-08010, Barcelona, Spain.
| | - Patricia Ferreira
- Department of Biochemistry and Cellular and Molecular Biology, and BIFI, University of Zaragoza, E-50009, Zaragoza, Spain.
| | - Angel T Martínez
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040, Madrid, Spain.
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Carro J, Fernández-Fueyo E, Fernández-Alonso C, Cañada J, Ullrich R, Hofrichter M, Alcalde M, Ferreira P, Martínez AT. Self-sustained enzymatic cascade for the production of 2,5-furandicarboxylic acid from 5-methoxymethylfurfural. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:86. [PMID: 29619082 PMCID: PMC5880071 DOI: 10.1186/s13068-018-1091-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 03/21/2018] [Indexed: 05/25/2023]
Abstract
BACKGROUND 2,5-Furandicarboxylic acid is a renewable building block for the production of polyfurandicarboxylates, which are biodegradable polyesters expected to substitute their classical counterparts derived from fossil resources. It may be produced from bio-based 5-hydroxymethylfurfural or 5-methoxymethylfurfural, both obtained by the acidic dehydration of biomass-derived fructose. 5-Methoxymethylfurfural, which is produced in the presence of methanol, generates less by-products and exhibits better storage stability than 5-hydroxymethylfurfural being, therefore, the industrial substrate of choice. RESULTS In this work, an enzymatic cascade involving three fungal oxidoreductases has been developed for the production of 2,5-furandicarboxylic acid from 5-methoxymethylfurfural. Aryl-alcohol oxidase and unspecific peroxygenase act on 5-methoxymethylfurfural and its partially oxidized derivatives yielding 2,5-furandicarboxylic acid, as well as methanol as a by-product. Methanol oxidase takes advantage of the methanol released for in situ producing H2O2 that, along with that produced by aryl-alcohol oxidase, fuels the peroxygenase reactions. In this way, the enzymatic cascade proceeds independently, with the only input of atmospheric O2, to attain a 70% conversion of initial 5-methoxymethylfurfural. The addition of some exogenous methanol to the reaction further improves the yield to attain an almost complete conversion of 5-methoxymethylfurfural into 2,5-furandicarboxylic acid. CONCLUSIONS The synergistic action of aryl-alcohol oxidase and unspecific peroxygenase in the presence of 5-methoxymethylfurfural and O2 is sufficient for the production of 2,5-furandicarboxylic acid. The addition of methanol oxidase to the enzymatic cascade increases the 2,5-furandicarboxylic acid yields by oxidizing a reaction by-product to fuel the peroxygenase reactions.
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Affiliation(s)
- Juan Carro
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain
| | - Elena Fernández-Fueyo
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain
| | | | - Javier Cañada
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain
| | - René Ullrich
- Department of Bio- and Environmental Sciences, International Institute Zittau - Technische Universität Dresden, Markt 23, 02763 Zittau, Germany
| | - Martin Hofrichter
- Department of Bio- and Environmental Sciences, International Institute Zittau - Technische Universität Dresden, Markt 23, 02763 Zittau, Germany
| | - Miguel Alcalde
- Department of Biocatalysis, Institute of Catalysis, CSIC, Marie Curie 2, E-28049 Madrid, Spain
| | - Patricia Ferreira
- Department of Biochemistry and Molecular and Cellular Biology and BIFI, University of Zaragoza, E-50009 Saragossa, Spain
| | - Angel T. Martínez
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain
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van Schie MMCH, Pedroso de Almeida T, Laudadio G, Tieves F, Fernández-Fueyo E, Noël T, Arends IWCE, Hollmann F. Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor. Beilstein J Org Chem 2018; 14:697-703. [PMID: 29719567 PMCID: PMC5905246 DOI: 10.3762/bjoc.14.58] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 03/15/2018] [Indexed: 01/03/2023] Open
Abstract
The biocatalytic preparation of trans-hex-2-enal from trans-hex-2-enol using a novel aryl alcohol oxidase from Pleurotus eryngii (PeAAOx) is reported. As O2-dependent enzyme PeAAOx-dependent reactions are generally plagued by the poor solubility of O2 in aqueous media and mass transfer limitations resulting in poor reaction rates. These limitations were efficiently overcome by conducting the reaction in a flow-reactor setup reaching unpreceded catalytic activities for the enzyme in terms of turnover frequency (up to 38 s−1) and turnover numbers (more than 300000) pointing towards preparative usefulness of the proposed reaction scheme.
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Affiliation(s)
- Morten M C H van Schie
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Tiago Pedroso de Almeida
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Gabriele Laudadio
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry & Process Technology, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Florian Tieves
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | | | - Timothy Noël
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry & Process Technology, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Isabel W C E Arends
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Frank Hollmann
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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Carro J, Ferreira P, Martínez AT, Gadda G. Stepwise Hydrogen Atom and Proton Transfers in Dioxygen Reduction by Aryl-Alcohol Oxidase. Biochemistry 2018; 57:1790-1797. [DOI: 10.1021/acs.biochem.8b00106] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Juan Carro
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain
| | - Patricia Ferreira
- Departament of Biochemistry and Cellular and Molecular Biology and Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, E-50009 Zaragoza, Spain
| | - Angel T. Martínez
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain
| | - Giovanni Gadda
- Department of Chemistry, Department of Biology, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30302-3965, United States
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30
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Carro J, Martínez-Júlvez M, Medina M, Martínez AT, Ferreira P. Protein dynamics promote hydride tunnelling in substrate oxidation by aryl-alcohol oxidase. Phys Chem Chem Phys 2018; 19:28666-28675. [PMID: 29043303 DOI: 10.1039/c7cp05904c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The temperature dependence of hydride transfer from the substrate to the N5 of the FAD cofactor during the reductive half-reaction of Pleurotus eryngii aryl-alcohol oxidase (AAO) is assessed here. Kinetic isotope effects on both the pre-steady state reduction of the enzyme and its steady-state kinetics, with differently deuterated substrates, suggest an environmentally-coupled quantum-mechanical tunnelling process. Moreover, those kinetic data, along with the crystallographic structure of the enzyme in complex with a substrate analogue, indicate that AAO shows a pre-organized active site that would only require the approaching of the hydride donor and acceptor for the tunnelled transfer to take place. Modification of the enzyme's active-site architecture by replacement of Tyr92, a residue establishing hydrophobic interactions with the substrate analogue in the crystal structure, in the Y92F, Y92L and Y92W variants resulted in different temperature dependence patterns that indicated a role of this residue in modulating the transfer reaction.
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Affiliation(s)
- Juan Carro
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040, Madrid, Spain.
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31
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Analysis of Agaricus meleagris pyranose dehydrogenase N-glycosylation sites and performance of partially non-glycosylated enzymes. Enzyme Microb Technol 2017; 99:57-66. [PMID: 28193332 DOI: 10.1016/j.enzmictec.2017.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/17/2017] [Accepted: 01/20/2017] [Indexed: 11/22/2022]
Abstract
Pyranose Dehydrogenase 1 from the basidiomycete Agaricus meleagris (AmPDH1) is an oxidoreductase capable of oxidizing a broad variety of sugars. Due to this and its ability of dioxidation of substrates and no side production of hydrogen peroxide, it is studied for use in enzymatic bio-fuel cells. In-vitro deglycosylated AmPDH1 as well as knock-out mutants of the N-glycosylation sites N75 and N175, near the active site entrance, were previously shown to improve achievable current densities of graphite electrodes modified with AmPDH1 and an osmium redox polymer acting as a redox mediator, up to 10-fold. For a better understanding of the role of N-glycosylation of AmPDH1, a systematic set of N-glycosylation site mutants was investigated in this work, regarding expression efficiency, enzyme activity and stability. Furthermore, the site specific extend of N-glycosylation was compared between native and recombinant wild type AmPDH1. Knocking out the site N252 prevented the attachment of significantly extended N-glycan structures as detected on polyacrylamide gel electrophoresis, but did not significantly alter enzyme performance on modified electrodes. This suggests that not the molecule size but other factors like accessibility of the active site improved performance of deglycosylated AmPDH1/osmium redox polymer modified electrodes. A fourth N-glycosylation site of AmPDH1 could be confirmed by mass spectrometry at N319, which appeared to be conserved in related fungal pyranose dehydrogenases but not in other members of the glucose-methanol-choline oxidoreductase structural family. This site was shown to be the only one that is essential for functional recombinant expression of the enzyme.
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32
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An aryl-alcohol oxidase of Pleurotus sapidus: heterologous expression, characterization, and application in a 2-enzyme system. Appl Microbiol Biotechnol 2016; 100:8021-30. [DOI: 10.1007/s00253-016-7567-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 04/12/2016] [Accepted: 04/18/2016] [Indexed: 10/21/2022]
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33
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Focused Directed Evolution of Aryl-Alcohol Oxidase in Saccharomyces cerevisiae by Using Chimeric Signal Peptides. Appl Environ Microbiol 2015; 81:6451-62. [PMID: 26162870 DOI: 10.1128/aem.01966-15] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 07/03/2015] [Indexed: 01/16/2023] Open
Abstract
Aryl-alcohol oxidase (AAO) is an extracellular flavoprotein that supplies ligninolytic peroxidases with H2O2 during natural wood decay. With a broad substrate specificity and highly stereoselective reaction mechanism, AAO is an attractive candidate for studies into organic synthesis and synthetic biology, and yet the lack of suitable heterologous expression systems has precluded its engineering by directed evolution. In this study, the native signal sequence of AAO from Pleurotus eryngii was replaced by those of the mating α-factor and the K1 killer toxin, as well as different chimeras of both prepro-leaders in order to drive secretion in Saccharomyces cerevisiae. The secretion of these AAO constructs increased in the following order: preproα-AAO > preαproK-AAO > preKproα-AAO > preproK-AAO. The chimeric preαproK-AAO was subjected to focused-directed evolution with the aid of a dual screening assay based on the Fenton reaction. Random mutagenesis and DNA recombination was concentrated on two protein segments (Met[α1]-Val109 and Phe392-Gln566), and an array of improved variants was identified, among which the FX7 mutant (harboring the H91N mutation) showed a dramatic 96-fold improvement in total activity with secretion levels of 2 mg/liter. Analysis of the N-terminal sequence of the FX7 variant confirmed the correct processing of the preαproK hybrid peptide by the KEX2 protease. FX7 showed higher stability in terms of pH and temperature, whereas the pH activity profiles and the kinetic parameters were maintained. The Asn91 lies in the flavin attachment loop motif, and it is a highly conserved residue in all members of the GMC superfamily, except for P. eryngii and P. pulmonarius AAO. The in vitro involution of the enzyme by restoring the consensus ancestor Asn91 promoted AAO expression and stability.
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34
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Heterologous expression of a fungal sterol esterase/lipase in different hosts: Effect on solubility, glycosylation and production. J Biosci Bioeng 2015; 120:637-43. [PMID: 25939548 DOI: 10.1016/j.jbiosc.2015.04.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 03/26/2015] [Accepted: 04/07/2015] [Indexed: 11/21/2022]
Abstract
Ophiostoma piceae secretes a versatile sterol-esterase (OPE) that shows high efficiency in both hydrolysis and synthesis of triglycerides and sterol esters. This enzyme produces aggregates in aqueous solutions, but the recombinant protein, expressed in Komagataella (synonym Pichia) pastoris, showed higher catalytic efficiency because of its higher solubility. This fact owes to a modification in the N-terminal sequence of the protein expressed in Pichia pastoris, which incorporated 4-8 additional amino acids, affecting its aggregation behavior. In this study we present a newly engineered P. pastoris strain with improved protein production. We also produced the recombinant protein in the yeast Saccharomyces cerevisiae and in the prokaryotic host Escherichia coli, corroborating that the presence of these N-terminal extra amino acids affected the protein's solubility. The OPE produced in the new P. pastoris strain presented the same physicochemical properties than the old one. An inactive form of the enzyme was produced by the bacterium, but the recombinant esterase from both yeasts was active even after its enzymatic deglycosylation, suggesting that the presence of N-linked carbohydrates in the mature protein is not essential for enzyme activity. Although the yield in S. cerevisiae was lower than that obtained in P. pastoris, this work demonstrates the importance of the choice of the heterologous host for successful production of soluble and active recombinant protein. In addition, S. cerevisiae constitutes a good engineering platform for improving the properties of this biocatalyst.
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35
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Ferreira P, Hernández-Ortega A, Lucas F, Carro J, Herguedas B, Borrelli KW, Guallar V, Martínez AT, Medina M. Aromatic stacking interactions govern catalysis in aryl-alcohol oxidase. FEBS J 2015; 282:3091-106. [PMID: 25639975 DOI: 10.1111/febs.13221] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/10/2015] [Accepted: 01/28/2015] [Indexed: 01/05/2023]
Abstract
Aryl-alcohol oxidase (AAO, EC 1.1.3.7) generates H2 O2 for lignin degradation at the expense of benzylic and other π system-containing primary alcohols, which are oxidized to the corresponding aldehydes. Ligand diffusion studies on Pleurotus eryngii AAO showed a T-shaped stacking interaction between the Tyr92 side chain and the alcohol substrate at the catalytically competent position for concerted hydride and proton transfers. Bi-substrate kinetics analysis revealed that reactions with 3-chloro- or 3-fluorobenzyl alcohols (halogen substituents) proceed via a ping-pong mechanism. However, mono- and dimethoxylated substituents (in 4-methoxybenzyl and 3,4-dimethoxybenzyl alcohols) altered the mechanism and a ternary complex was formed. Electron-withdrawing substituents resulted in lower quantum mechanics stacking energies between aldehyde and the tyrosine side chain, contributing to product release, in agreement with the ping-pong mechanism observed in 3-chloro- and 3-fluorobenzyl alcohol kinetics analysis. In contrast, the higher stacking energies when electron donor substituents are present result in reaction of O2 with the flavin through a ternary complex, in agreement with the kinetics of methoxylated alcohols. The contribution of Tyr92 to the AAO reaction mechanism was investigated by calculation of stacking interaction energies and site-directed mutagenesis. Replacement of Tyr92 by phenylalanine does not alter the AAO kinetic constants (on 4-methoxybenzyl alcohol), most probably because the stacking interaction is still possible. However, introduction of a tryptophan residue at this position strongly reduced the affinity for the substrate (i.e. the pre-steady state Kd and steady-state Km increase by 150-fold and 75-fold, respectively), and therefore the steady-state catalytic efficiency, suggesting that proper stacking is impossible with this bulky residue. The above results confirm the role of Tyr92 in substrate binding, thus governing the kinetic mechanism in AAO.
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Affiliation(s)
- Patricia Ferreira
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, and Instituto de Biocomputación y Física de Sistemas Complejos, Zaragoza, Spain
| | - Aitor Hernández-Ortega
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Fátima Lucas
- Joint Barcelona Supercomputing Center-Centre for Genomic Regulation-Institute for Research in Biomedicine Research Program in Computational Biology, Barcelona Supercomputing Center, Barcelona, Spain
| | - Juan Carro
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Beatriz Herguedas
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, and Instituto de Biocomputación y Física de Sistemas Complejos, Zaragoza, Spain
| | - Kenneth W Borrelli
- Joint Barcelona Supercomputing Center-Centre for Genomic Regulation-Institute for Research in Biomedicine Research Program in Computational Biology, Barcelona Supercomputing Center, Barcelona, Spain
| | - Victor Guallar
- Joint Barcelona Supercomputing Center-Centre for Genomic Regulation-Institute for Research in Biomedicine Research Program in Computational Biology, Barcelona Supercomputing Center, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Angel T Martínez
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Milagros Medina
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, and Instituto de Biocomputación y Física de Sistemas Complejos, Zaragoza, Spain
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36
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Carro J, Ferreira P, Rodríguez L, Prieto A, Serrano A, Balcells B, Ardá A, Jiménez‐Barbero J, Gutiérrez A, Ullrich R, Hofrichter M, Martínez AT. 5‐hydroxymethylfurfural conversion by fungal aryl‐alcohol oxidase and unspecific peroxygenase. FEBS J 2015; 282:3218-29. [DOI: 10.1111/febs.13177] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/05/2014] [Accepted: 12/10/2014] [Indexed: 01/11/2023]
Affiliation(s)
- Juan Carro
- Centro de Investigaciones Biológicas Consejo Superior de Investigaciones Científicas Madrid Spain
| | - Patricia Ferreira
- Facultad de Ciencias and Instituto de Biocomputación y Física de Sistemas Complejos Zaragoza Spain
| | - Leonor Rodríguez
- Centro de Investigaciones Biológicas Consejo Superior de Investigaciones Científicas Madrid Spain
| | - Alicia Prieto
- Centro de Investigaciones Biológicas Consejo Superior de Investigaciones Científicas Madrid Spain
| | - Ana Serrano
- Centro de Investigaciones Biológicas Consejo Superior de Investigaciones Científicas Madrid Spain
| | - Beatriz Balcells
- Centro de Investigaciones Biológicas Consejo Superior de Investigaciones Científicas Madrid Spain
| | - Ana Ardá
- Centro de Investigaciones Biológicas Consejo Superior de Investigaciones Científicas Madrid Spain
| | - Jesús Jiménez‐Barbero
- Centro de Investigaciones Biológicas Consejo Superior de Investigaciones Científicas Madrid Spain
| | - Ana Gutiérrez
- Instituto de Recursos Naturales y Agrobiología de Sevilla Consejo Superior de Investigaciones Científicas Seville Spain
| | - René Ullrich
- Department of Bio‐ and Environmental Sciences International Institute of Zittau Germany
| | - Martin Hofrichter
- Department of Bio‐ and Environmental Sciences International Institute of Zittau Germany
| | - Angel T. Martínez
- Centro de Investigaciones Biológicas Consejo Superior de Investigaciones Científicas Madrid Spain
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Zelena K, Eisele N, Berger RG. Escherichia coli as a production host for novel enzymes from basidiomycota. Biotechnol Adv 2014; 32:1382-95. [DOI: 10.1016/j.biotechadv.2014.08.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/14/2014] [Accepted: 08/25/2014] [Indexed: 01/14/2023]
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38
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Chakraborty M, Goel M, Chinnadayyala SR, Dahiya UR, Ghosh SS, Goswami P. Molecular characterization and expression of a novel alcohol oxidase from Aspergillus terreus MTCC6324. PLoS One 2014; 9:e95368. [PMID: 24752075 PMCID: PMC3994049 DOI: 10.1371/journal.pone.0095368] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 03/26/2014] [Indexed: 11/28/2022] Open
Abstract
The alcohol oxidase (AOx) cDNA from Aspergillus terreus MTCC6324 with an open reading frame (ORF) of 2001 bp was constructed from n-hexadecane induced cells and expressed in Escherichia coli with a yield of ∼4.2 mg protein g−1 wet cell. The deduced amino acid sequences of recombinant rAOx showed maximum structural homology with the chain B of aryl AOx from Pleurotus eryngii. A functionally active AOx was achieved by incubating the apo-AOx with flavin adenine dinucleotide (FAD) for ∼80 h at 16°C and pH 9.0. The isoelectric point and mass of the apo-AOx were found to be 6.5±0.1 and ∼74 kDa, respectively. Circular dichroism data of the rAOx confirmed its ordered structure. Docking studies with an ab-initio protein model demonstrated the presence of a conserved FAD binding domain with an active substrate binding site. The rAOx was specific for aryl alcohols and the order of its substrate preference was 4-methoxybenzyl alcohol >3-methoxybenzyl alcohol>3, 4-dimethoxybenzyl alcohol > benzyl alcohol. A significantly high aggregation to ∼1000 nm (diameter) and catalytic efficiency (kcat/Km) of 7829.5 min−1 mM−1 for 4-methoxybenzyl alcohol was also demonstrated for rAOx. The results infer the novelty of the AOx and its potential biocatalytic application.
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Affiliation(s)
- Mitun Chakraborty
- Department of Biotechnology, Indian Institute of Technology Guwahati, Assam, India
| | - Manish Goel
- Department of Biotechnology, Indian Institute of Technology Guwahati, Assam, India
| | | | - Ujjwal Ranjan Dahiya
- Department of Biotechnology, Indian Institute of Technology Guwahati, Assam, India
| | - Siddhartha Sankar Ghosh
- Department of Biotechnology, Indian Institute of Technology Guwahati, Assam, India
- * E-mail: (SSG); (PG)
| | - Pranab Goswami
- Department of Biotechnology, Indian Institute of Technology Guwahati, Assam, India
- * E-mail: (SSG); (PG)
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Biochemical analysis of recombinant AlkJ from Pseudomonas putida reveals a membrane-associated, flavin adenine dinucleotide-dependent dehydrogenase suitable for the biosynthetic production of aliphatic aldehydes. Appl Environ Microbiol 2014; 80:2468-77. [PMID: 24509930 DOI: 10.1128/aem.04297-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The noncanonical alcohol dehydrogenase AlkJ is encoded on the alkane-metabolizing alk operon of the mesophilic bacterium Pseudomonas putida GPo1. To gain insight into the enzymology of AlkJ, we have produced the recombinant protein in Escherichia coli and purified it to homogeneity using His6 tag affinity and size exclusion chromatography (SEC). Despite synthesis in the cytoplasm, AlkJ was associated with the bacterial cell membrane, and solubilization with n-dodecyl-β-D-maltoside was necessary to liberate the enzyme. SEC and spectrophotometric analysis revealed a dimeric quaternary structure with stoichiometrically bound reduced flavin adenine dinucleotide (FADH2). The holoenzyme showed thermal denaturation at moderate temperatures around 35°C, according to both activity assay and temperature-dependent circular dichroism spectroscopy. The tightly bound coenzyme was released only upon denaturation with SDS or treatment with urea-KBr and, after air oxidation, exhibited the characteristic absorption spectrum of FAD. The enzymatic activity of purified AlkJ for 1-butanol, 1-hexanol, and 1-octanol as well as the n-alkanol derivative ω-hydroxy lauric acid methyl ester (HLAMe) was quantified in the presence of the artificial electron acceptors phenazine methosulfate (PMS) and 2,6-dichlorophenolindophenol (DCPIP), indicating broad substrate specificity with the lowest activity on the shortest alcohol, 1-butanol. Furthermore, AlkJ was able to accept as cosubstrates/oxidants the ubiquinone derivatives Q0 and Q1, also in conjunction with cytochrome c, which suggests coupling to the bacterial respiratory chain of this membrane-associated enzyme in its physiological environment. Using gas chromatographic analysis, we demonstrated specific biocatalytic conversion by AlkJ of the substrate HLAMe to the industrially relevant aldehyde, thus enabling the biotechnological production of 12-amino lauric acid methyl ester via subsequent enzymatic transamination.
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An overview on alcohol oxidases and their potential applications. Appl Microbiol Biotechnol 2013; 97:4259-75. [DOI: 10.1007/s00253-013-4842-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 03/06/2013] [Accepted: 03/07/2013] [Indexed: 10/27/2022]
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Hernández-Ortega A, Lucas F, Ferreira P, Medina M, Guallar V, Martínez AT. Role of Active Site Histidines in the Two Half-Reactions of the Aryl-Alcohol Oxidase Catalytic Cycle. Biochemistry 2012; 51:6595-608. [DOI: 10.1021/bi300505z] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Fátima Lucas
- Joint BSC-IRB
Research Program
in Computational Biology, Barcelona Supercomputing Center, Jordi Girona 29, E-08034 Barcelona, Spain
| | - Patricia Ferreira
- Department of Biochemistry and
Molecular and Cellular Biology and Institute of Biocomputation and
Physics of Complex Systems, University of Zaragoza, E-50009 Zaragoza, Spain
| | - Milagros Medina
- Department of Biochemistry and
Molecular and Cellular Biology and Institute of Biocomputation and
Physics of Complex Systems, University of Zaragoza, E-50009 Zaragoza, Spain
| | - Victor Guallar
- Joint BSC-IRB
Research Program
in Computational Biology, Barcelona Supercomputing Center, Jordi Girona 29, E-08034 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, E-08010 Barcelona, Spain
| | - Angel T. Martínez
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040
Madrid, Spain
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Hernández-Ortega A, Ferreira P, Merino P, Medina M, Guallar V, Martínez AT. Stereoselective Hydride Transfer by Aryl-Alcohol Oxidase, a Member of the GMC Superfamily. Chembiochem 2012; 13:427-35. [PMID: 22271643 DOI: 10.1002/cbic.201100709] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Indexed: 11/06/2022]
Affiliation(s)
- Aitor Hernández-Ortega
- Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
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Fungal aryl-alcohol oxidase: a peroxide-producing flavoenzyme involved in lignin degradation. Appl Microbiol Biotechnol 2012; 93:1395-410. [DOI: 10.1007/s00253-011-3836-8] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 12/06/2011] [Accepted: 12/09/2011] [Indexed: 11/30/2022]
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Tamboli DP, Telke AA, Dawkar VV, Jadhav SB, Govindwar SP. Purification and characterization of bacterial aryl alcohol oxidase from Sphingobacterium sp. ATM and its uses in textile dye decolorization. BIOTECHNOL BIOPROC E 2011. [DOI: 10.1007/s12257-011-0031-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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45
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Hernández-Ortega A, Lucas F, Ferreira P, Medina M, Guallar V, Martínez AT. Modulating O2 reactivity in a fungal flavoenzyme: involvement of aryl-alcohol oxidase Phe-501 contiguous to catalytic histidine. J Biol Chem 2011; 286:41105-14. [PMID: 21940622 DOI: 10.1074/jbc.m111.282467] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aryl-alcohol oxidase (AAO) is a flavoenzyme responsible for activation of O(2) to H(2)O(2) in fungal degradation of lignin. The AAO crystal structure shows a buried active site connected to the solvent by a hydrophobic funnel-shaped channel, with Phe-501 and two other aromatic residues forming a narrow bottleneck that prevents the direct access of alcohol substrates. However, ligand diffusion simulations show O(2) access to the active site following this channel. Site-directed mutagenesis of Phe-501 yielded a F501A variant with strongly reduced O(2) reactivity. However, a variant with increased reactivity, as shown by kinetic constants and steady-state oxidation degree, was obtained by substitution of Phe-501 with tryptophan. The high oxygen catalytic efficiency of F501W, ∼2-fold that of native AAO and ∼120-fold that of F501A, seems related to a higher O(2) availability because the turnover number was slightly decreased with respect to the native enzyme. Free diffusion simulations of O(2) inside the active-site cavity of AAO (and several in silico Phe-501 variants) yielded >60% O(2) population at 3-4 Å from flavin C4a in F501W compared with 44% in AAO and only 14% in F501A. Paradoxically, the O(2) reactivity of AAO decreased when the access channel was enlarged and increased when it was constricted by introducing a tryptophan residue. This is because the side chain of Phe-501, contiguous to the catalytic histidine (His-502 in AAO), helps to position O(2) at an adequate distance from flavin C4a (and His-502 Nε). Phe-501 substitution with a bulkier tryptophan residue resulted in an increase in the O(2) reactivity of this flavoenzyme.
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Affiliation(s)
- Aitor Hernández-Ortega
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, E-28040 Madrid, Spain
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Substrate diffusion and oxidation in GMC oxidoreductases: an experimental and computational study on fungal aryl-alcohol oxidase. Biochem J 2011; 436:341-50. [DOI: 10.1042/bj20102090] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AAO (aryl-alcohol oxidase) provides H2O2 in fungal degradation of lignin, a process of high biotechnological interest. The crystal structure of AAO does not show open access to the active site, where different aromatic alcohols are oxidized. In the present study we investigated substrate diffusion and oxidation in AAO compared with the structurally related CHO (choline oxidase). Cavity finder and ligand diffusion simulations indicate the substrate-entrance channel, requiring side-chain displacements and involving a stacking interaction with Tyr92. Mixed QM (quantum mechanics)/MM (molecular mechanics) studies combined with site-directed mutagenesis showed two active-site catalytic histidine residues, whose substitution strongly decreased both catalytic and transient-state reduction constants for p-anisyl alcohol in the H502A (over 1800-fold) and H546A (over 35-fold) variants. Combination of QM/MM energy profiles, protonation predictors, molecular dynamics, mutagenesis and pH profiles provide a robust answer regarding the nature of the catalytic base. The histidine residue in front of the FAD ring, AAO His502 (and CHO His466), acts as a base. For the two substrates assayed, it was shown that proton transfer preceded hydride transfer, although both processes are highly coupled. No stable intermediate was observed in the energy profiles, in contrast with that observed for CHO. QM/MM, together with solvent KIE (kinetic isotope effect) results, suggest a non-synchronous concerted mechanism for alcohol oxidation by AAO.
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Kinetic and chemical characterization of aldehyde oxidation by fungal aryl-alcohol oxidase. Biochem J 2010; 425:585-93. [PMID: 19891608 DOI: 10.1042/bj20091499] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Fungal AAO (aryl-alcohol oxidase) provides H2O2 for lignin biodegradation. AAO is active on benzyl alcohols that are oxidized to aldehydes. However, during oxidation of some alcohols, AAO forms more than a stoichiometric number of H2O2 molecules with respect to the amount of aldehyde detected due to a double reaction that involves aryl-aldehyde oxidase activity. The latter reaction was investigated using different benzylic aldehydes, whose oxidation to acids was demonstrated by GC-MS. The steady- and presteady state kinetic constants, together with the chromatographic results, revealed that the presence of substrate electron-withdrawing or electron-donating substituents had a strong influence on activity; the highest activity was with p-nitrobenzaldehyde and halogenated aldehydes and the lowest with methoxylated aldehydes. Moreover, activity was correlated to the aldehyde hydration rates estimated by 1H-NMR. These findings, together with the absence in the AAO active site of a residue able to drive oxidation via an aldehyde thiohemiacetal, suggested that oxidation mainly proceeds via the gem-diol species. The reaction mechanism (with a solvent isotope effect, 2H2Okred, of approx. 1.5) would be analogous to that described for alcohols, the reductive half-reaction involving concerted hydride transfer from the alpha-carbon and proton abstraction from one of the gem-diol hydroxy groups by a base. The existence of two steps of opposite polar requirements (hydration and hydride transfer) explains some aspects of aldehyde oxidation by AAO. Site-directed mutagenesis identified two histidine residues strongly involved in gem-diol oxidation and, unexpectedly, suggested that an active-site tyrosine residue could facilitate the oxidation of some aldehydes that show no detectable hydration. Double alcohol and aldehyde oxidase activities of AAO would contribute to H2O2 supply by the enzyme.
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Ferreira P, Hernandez-Ortega A, Herguedas B, Martínez AT, Medina M. Aryl-alcohol oxidase involved in lignin degradation: a mechanistic study based on steady and pre-steady state kinetics and primary and solvent isotope effects with two alcohol substrates. J Biol Chem 2009; 284:24840-7. [PMID: 19574215 DOI: 10.1074/jbc.m109.011593] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aryl-alcohol oxidase (AAO) is a FAD-containing enzyme in the GMC (glucose-methanol-choline oxidase) family of oxidoreductases. AAO participates in fungal degradation of lignin, a process of high ecological and biotechnological relevance, by providing the hydrogen peroxide required by ligninolytic peroxidases. In the Pleurotus species, this peroxide is generated in the redox cycling of p-anisaldehyde, an extracellular fungal metabolite. In addition to p-anisyl alcohol, the enzyme also oxidizes other polyunsaturated primary alcohols. Its reaction mechanism was investigated here using p-anisyl alcohol and 2,4-hexadien-1-ol as two AAO model substrates. Steady state kinetic parameters and enzyme-monitored turnover were consistent with a sequential mechanism in which O(2) reacts with reduced AAO before release of the aldehyde product. Pre-steady state analysis revealed that the AAO reductive half-reaction is essentially irreversible and rate limiting during catalysis. Substrate and solvent kinetic isotope effects under steady and pre-steady state conditions (the latter showing approximately 9-fold slower enzyme reduction when alpha-bideuterated substrates were used, and approximately 13-fold slower reduction when both substrate and solvent effects were simultaneously evaluated) revealed a synchronous mechanism in which hydride transfer from substrate alpha-carbon to FAD and proton abstraction from hydroxyl occur simultaneously. This significantly differs from the general mechanism proposed for other members of the GMC oxidoreductase family that implies hydride transfer from a previously stabilized substrate alkoxide.
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Affiliation(s)
- Patricia Ferreira
- Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas (CSIC), E28040 Madrid, Spain
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Stajic´ M, Vukojevic´ J, Duletic´-Lauševic´ S. Biology ofPleurotus eryngiiand role in biotechnological processes: a review. Crit Rev Biotechnol 2009; 29:55-66. [DOI: 10.1080/07388550802688821] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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50
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Munteanu FD, Ferreira P, Ruiz-Dueñas FJ, Martínez AT, Cavaco-Paulo A. Bioelectrochemical investigations of aryl-alcohol oxidase from Pleurotus eryngii. J Electroanal Chem (Lausanne) 2008. [DOI: 10.1016/j.jelechem.2008.02.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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