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Forsberg Z, Tuveng TR, Eijsink VGH. A modular enzyme with combined hemicellulose-removing and LPMO activity increases cellulose accessibility in softwood. FEBS J 2024. [PMID: 39190632 DOI: 10.1111/febs.17250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 07/05/2024] [Accepted: 08/13/2024] [Indexed: 08/29/2024]
Abstract
Because of the association with other complex polysaccharides, extracting and utilizing cellulose from lignocellulosic materials requires the combined action of a broad range of carbohydrate-active enzymes, including multiple glycoside hydrolases (GHs) and lytic polysaccharide monooxygenases (LPMOs). The interplay between these enzymes and the way in which Nature orchestrates their co-existence and combined action are topics of great scientific and industrial interest. To gain more insight into these issues, we have studied the lignocellulose-degrading abilities of an enzyme from Caldibacillus cellulovorans (CcLPMO10-Man5), comprising an LPMO domain, a GH5 mannanase domain and two family 3 carbohydrate-binding modules (CBM3). Using a natural softwood substrate, we show that this enzyme promotes cellulase activity, i.e., saccharification of cellulose, both by removing mannan covering the cellulose and by oxidatively breaking up the cellulose structure. Synergy with CcLPMO10-Man5 was most pronounced for two tested cellobiohydrolases, whereas effects were smaller for a tested endoglucanase, which is in line with the notion that cellobiohydrolases and LPMOs attack the same crystalline regions of the cellulose, whereas endoglucanases attack semi-crystalline and amorphous regions. Importantly, the LPMO domain of CcLPMO10-Man5 is incapable of accessing the softwood cellulose in absence of the mannanase domain. Considering that LPMOs not bound to a substrate are sensitive to autocatalytic inactivation, this intramolecular synergy provides a perfect rationale for the evolution of modular enzymes such as CcLPMO10-Man5. The intramolecular coupling of the LPMO with a mannanase and two CBMs ensures that the LPMO is directed to areas where mannans are removed and cellulose thus becomes available.
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Affiliation(s)
- Zarah Forsberg
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Tina R Tuveng
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
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2
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Støpamo FG, Sulaeva I, Budischowsky D, Rahikainen J, Marjamaa K, Kruus K, Potthast A, Eijsink VGH, Várnai A. The impact of the carbohydrate-binding module on how a lytic polysaccharide monooxygenase modifies cellulose fibers. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:118. [PMID: 39182111 PMCID: PMC11344300 DOI: 10.1186/s13068-024-02564-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 08/09/2024] [Indexed: 08/27/2024]
Abstract
BACKGROUND In recent years, lytic polysaccharide monooxygenases (LPMOs) that oxidatively cleave cellulose have gained increasing attention in cellulose fiber modification. LPMOs are relatively small copper-dependent redox enzymes that occur as single domain proteins but may also contain an appended carbohydrate-binding module (CBM). Previous studies have indicated that the CBM "immobilizes" the LPMO on the substrate and thus leads to more localized oxidation of the fiber surface. Still, our understanding of how LPMOs and their CBMs modify cellulose fibers remains limited. RESULTS Here, we studied the impact of the CBM on the fiber-modifying properties of NcAA9C, a two-domain family AA9 LPMO from Neurospora crassa, using both biochemical methods as well as newly developed multistep fiber dissolution methods that allow mapping LPMO action across the fiber, from the fiber surface to the fiber core. The presence of the CBM in NcAA9C improved binding towards amorphous (PASC), natural (Cell I), and alkali-treated (Cell II) cellulose, and the CBM was essential for significant binding of the non-reduced LPMO to Cell I and Cell II. Substrate binding of the catalytic domain was promoted by reduction, allowing the truncated CBM-free NcAA9C to degrade Cell I and Cell II, albeit less efficiently and with more autocatalytic enzyme degradation compared to the full-length enzyme. The sequential dissolution analyses showed that cuts by the CBM-free enzyme are more evenly spread through the fiber compared to the CBM-containing full-length enzyme and showed that the truncated enzyme can penetrate deeper into the fiber, thus giving relatively more oxidation and cleavage in the fiber core. CONCLUSIONS These results demonstrate the capability of LPMOs to modify cellulose fibers from surface to core and reveal how variation in enzyme modularity can be used to generate varying cellulose-based materials. While the implications of these findings for LPMO-based cellulose fiber engineering remain to be explored, it is clear that the presence of a CBM is an important determinant of the three-dimensional distribution of oxidation sites in the fiber.
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Affiliation(s)
| | - Irina Sulaeva
- University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - David Budischowsky
- University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | | | - Kaisa Marjamaa
- VTT Technical Research Centre of Finland, Espoo, Finland
| | - Kristiina Kruus
- VTT Technical Research Centre of Finland, Espoo, Finland
- Aalto University, Espoo, Finland
| | - Antje Potthast
- University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | | | - Anikó Várnai
- Norwegian University of Life Sciences (NMBU), Ås, Norway.
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Truong NH, Le TTH, Nguyen HD, Nguyen HT, Dao TK, Tran TMN, Tran HL, Nguyen DT, Nguyen TQ, Phan THT, Do TH, Phan NH, Ngo TCN, Vu VV. Sequence and structure analyses of lytic polysaccharide monooxygenases mined from metagenomic DNA of humus samples around white-rot fungi in Cuc Phuong tropical forest, Vietnam. PeerJ 2024; 12:e17553. [PMID: 38938609 PMCID: PMC11210479 DOI: 10.7717/peerj.17553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 05/20/2024] [Indexed: 06/29/2024] Open
Abstract
Background White-rot fungi and bacteria communities are unique ecosystems with different types of symbiotic interactions occurring during wood decomposition, such as cooperation, mutualism, nutritional competition, and antagonism. The role of chitin-active lytic polysaccharide monooxygenases (LPMOs) in these symbiotic interactions is the subject of this study. Method In this study, bioinformatics tools were used to analyze the sequence and structure of putative LPMOs mined by hidden Markov model (HMM) profiles from the bacterial metagenomic DNA database of collected humus samples around white-rot fungi in Cuc Phuong primary forest, Vietnam. Two genes encoding putative LPMOs were expressed in E. coli and purified for enzyme activity assay. Result Thirty-one full-length proteins annotated as putative LPMOs according to HMM profiles were confirmed by amino acid sequence comparison. The comparison results showed that although the amino acid sequences of the proteins were very different, they shared nine conserved amino acids, including two histidine and one phenylalanine that characterize the H1-Hx-Yz motif of the active site of bacterial LPMOs. Structural analysis of these proteins revealed that they are multidomain proteins with different functions. Prediction of the catalytic domain 3-D structure of these putative LPMOs using Alphafold2 showed that their spatial structures were very similar in shape, although their protein sequences were very different. The results of testing the activity of proteins GL0247266 and GL0183513 show that they are chitin-active LPMOs. Prediction of the 3-D structures of these two LPMOs using Alphafold2 showed that GL0247266 had five functional domains, while GL0183513 had four functional domains, two of which that were similar to the GbpA_2 and GbpA_3 domains of protein GbpA of Vibrio cholerae bacteria. The GbpA_2 - GbpA_3 complex was also detected in 11 other proteins. Based on the structural characteristics of functional domains, it is possible to hypothesize the role of chitin-active GbpA-like LPMOs in the relationship between fungal and bacterial communities coexisting on decomposing trees in primary forests.
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Affiliation(s)
- Nam-Hai Truong
- Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
- Graduate University of Science and Technology (GUST), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | - Thi-Thu-Hong Le
- Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
- Graduate University of Science and Technology (GUST), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | - Hong-Duong Nguyen
- Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | | | - Trong-Khoa Dao
- Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | - Thi-Minh-Nguyet Tran
- The Key Laboratory of Enzyme and Protein Technology (KLEPT), VNU University of Science, Hanoi, Vietnam
| | - Huyen-Linh Tran
- Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | - Dinh-Trong Nguyen
- Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | - Thi-Quy Nguyen
- Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | - Thi-Hong-Thao Phan
- Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | - Thi-Huyen Do
- Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
- Graduate University of Science and Technology (GUST), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | - Ngoc-Han Phan
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh, Vietnam
| | - Thi-Cam-Nhung Ngo
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh, Vietnam
| | - Van-Van Vu
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh, Vietnam
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Decembrino D, Cannella D. The thin line between monooxygenases and peroxygenases. P450s, UPOs, MMOs, and LPMOs: A brick to bridge fields of expertise. Biotechnol Adv 2024; 72:108321. [PMID: 38336187 DOI: 10.1016/j.biotechadv.2024.108321] [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: 10/31/2023] [Revised: 02/04/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Many scientific fields, although driven by similar purposes and dealing with similar technologies, often appear so isolated and far from each other that even the vocabularies to describe the very same phenomenon might differ. Concerning the vast field of biocatalysis, a special role is played by those redox enzymes that employ oxygen-based chemistry to unlock transformations otherwise possible only with metal-based catalysts. As such, greener chemical synthesis methods and environmentally-driven biotechnological approaches were enabled over the last decades by the use of several enzymes and ultimately resulted in the first industrial applications. Among what can be called today the environmental biorefinery sector, biomass transformation, greenhouse gas reduction, bio-gas/fuels production, bioremediation, as well as bulk or fine chemicals and even pharmaceuticals manufacturing are all examples of fields in which successful prototypes have been demonstrated employing redox enzymes. In this review we decided to focus on the most prominent enzymes (MMOs, LPMO, P450 and UPO) capable of overcoming the ∼100 kcal mol-1 barrier of inactivated CH bonds for the oxyfunctionalization of organic compounds. Harnessing the enormous potential that lies within these enzymes is of extreme value to develop sustainable industrial schemes and it is still deeply coveted by many within the aforementioned fields of application. Hence, the ambitious scope of this account is to bridge the current cutting-edge knowledge gathered upon each enzyme. By creating a broad comparison, scientists belonging to the different fields may find inspiration and might overcome obstacles already solved by the others. This work is organised in three major parts: a first section will be serving as an introduction to each one of the enzymes regarding their structural and activity diversity, whereas a second one will be encompassing the mechanistic aspects of their catalysis. In this regard, the machineries that lead to analogous catalytic outcomes are depicted, highlighting the major differences and similarities. Finally, a third section will be focusing on the elements that allow the oxyfunctionalization chemistry to occur by delivering redox equivalents to the enzyme by the action of diverse redox partners. Redox partners are often overlooked in comparison to the catalytic counterparts, yet they represent fundamental elements to better understand and further develop practical applications based on mono- and peroxygenases.
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Affiliation(s)
- Davide Decembrino
- Photobiocatalysis Unit - Crop Production and Biostimulation Lab (CPBL), and Biomass Transformation Lab (BTL), École Interfacultaire de Bioingénieurs, Université Libre de Bruxelles, Belgium.
| | - David Cannella
- Photobiocatalysis Unit - Crop Production and Biostimulation Lab (CPBL), and Biomass Transformation Lab (BTL), École Interfacultaire de Bioingénieurs, Université Libre de Bruxelles, Belgium.
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5
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Wieduwilt EK, Lo Leggio L, Hedegård ED. A frontier-orbital view of the initial steps of lytic polysaccharide monooxygenase reactions. Dalton Trans 2024; 53:5796-5807. [PMID: 38445349 DOI: 10.1039/d3dt04275h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are copper enzymes that oxidatively cleave the strong C-H bonds in recalcitrant polysaccharide substrates, thereby playing a crucial role in biomass degradation. Recently, LPMOs have also been shown to be important for several pathogens. It is well established that the Cu(II) resting state of LPMOs is inactive, and the electronic structure of the active site needs to be altered to transform the enzyme into an active form. Whether this transformation occurs due to substrate binding or due to a unique priming reduction has remained speculative. Starting from four different crystal structures of the LPMO LsAA9A with well-defined oxidation states, we use a frontier molecular orbital approach to elucidate the initial steps of the LPMO reaction. We give an explanation for the requirement of the unique priming reduction and analyse electronic structure changes upon substrate binding. We further investigate how the presence of the substrate could facilitate an electron transfer from the copper active site to an H2O2 co-substrate. Our findings could help to control experimental LPMO reactions.
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Affiliation(s)
- Erna Katharina Wieduwilt
- Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
| | - Leila Lo Leggio
- Department of Chemistry, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Erik Donovan Hedegård
- Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
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Angeltveit CF, Várnai A, Eijsink VGH, Horn SJ. Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:39. [PMID: 38461298 PMCID: PMC10924376 DOI: 10.1186/s13068-024-02485-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 02/24/2024] [Indexed: 03/11/2024]
Abstract
BACKGROUND The polysaccharides in lignocellulosic biomass hold potential for production of biofuels and biochemicals. However, achieving efficient conversion of this resource into fermentable sugars faces challenges, especially when operating at industrially relevant high solid loadings. While it is clear that combining classical hydrolytic enzymes and lytic polysaccharide monooxygenases (LPMOs) is necessary to achieve high saccharification yields, exactly how these enzymes synergize at high solid loadings remains unclear. RESULTS An LPMO-poor cellulase cocktail, Celluclast 1.5 L, was spiked with one or both of two fungal LPMOs from Thermothielavioides terrestris and Thermoascus aurantiacus, TtAA9E and TaAA9A, respectively, to assess their impact on cellulose saccharification efficiency at high dry matter loading, using Avicel and steam-exploded wheat straw as substrates. The results demonstrate that LPMOs can mitigate the reduction in saccharification efficiency associated with high dry matter contents. The positive effect of LPMO inclusion depends on the type of feedstock and the type of LPMO and increases with the increasing dry matter content and reaction time. Furthermore, our results show that chelating free copper, which may leak out of the active site of inactivated LPMOs during saccharification, with EDTA prevents side reactions with in situ generated H2O2 and the reductant (ascorbic acid). CONCLUSIONS This study shows that sustaining LPMO activity is vital for efficient cellulose solubilization at high substrate loadings. LPMO cleavage of cellulose at high dry matter loadings results in new chain ends and thus increased water accessibility leading to decrystallization of the substrate, all factors making the substrate more accessible to cellulase action. Additionally, this work highlights the importance of preventing LPMO inactivation and its potential detrimental impact on all enzymes in the reaction.
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Affiliation(s)
- Camilla F Angeltveit
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Svein J Horn
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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7
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Angeltveit CF, Jeoh T, Horn SJ. Lytic polysaccharide monooxygenase activity increases productive binding capacity of cellobiohydrolases on cellulose. BIORESOURCE TECHNOLOGY 2023; 389:129806. [PMID: 37769978 DOI: 10.1016/j.biortech.2023.129806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/25/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Cellobiohydrolases are crucial for cellulose breakdown, but their efficiency on crystalline cellulose is hampered by limited access to single chain ends to initiate hydrolysis. As a result, they depend on enzymes like lytic polysaccharide monooxygenases (LPMOs), which directly target the crystalline cellulose surface. This study investigated how LPMO pretreatment affected the productive binding capacity of a Trichoderma longibrachiatum cellobiohydrolase, TlCBHI, on crystalline cellulose by applying an amperometric cellobiose dehydrogenase biosensor. After the 24-hour of LPMO pretreatment, the productive binding capacity of TlCBHI significantly increased in all reactions. However, with a shorter 5-hour LPMO pretreatment, minimal to no effect on productive binding capacity was observed. Of note, all LPMO reactions were inactivated around this time point. This delayed LPMO effect suggests that the improved binding capacity for cellulases does not directly result from cellulose chain cleavage by LPMOs but rather from the cellulose decrystallization following the oxidative cleavage.
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Affiliation(s)
- Camilla F Angeltveit
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Tina Jeoh
- Biological and Agricultural Engineering, University of California, Davis, United States
| | - Svein J Horn
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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8
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Forsberg Z, Stepnov AA, Tesei G, Wang Y, Buchinger E, Kristiansen SK, Aachmann FL, Arleth L, Eijsink VGH, Lindorff-Larsen K, Courtade G. The effect of linker conformation on performance and stability of a two-domain lytic polysaccharide monooxygenase. J Biol Chem 2023; 299:105262. [PMID: 37734553 PMCID: PMC10598543 DOI: 10.1016/j.jbc.2023.105262] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/05/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023] Open
Abstract
A considerable number of lytic polysaccharide monooxygenases (LPMOs) and other carbohydrate-active enzymes are modular, with catalytic domains being tethered to additional domains, such as carbohydrate-binding modules, by flexible linkers. While such linkers may affect the structure, function, and stability of the enzyme, their roles remain largely enigmatic, as do the reasons for natural variation in length and sequence. Here, we have explored linker functionality using the two-domain cellulose-active ScLPMO10C from Streptomyces coelicolor as a model system. In addition to investigating the WT enzyme, we engineered three linker variants to address the impact of both length and sequence and characterized these using small-angle X-ray scattering, NMR, molecular dynamics simulations, and functional assays. The resulting data revealed that, in the case of ScLPMO10C, linker length is the main determinant of linker conformation and enzyme performance. Both the WT and a serine-rich variant, which have the same linker length, demonstrated better performance compared with those with either a shorter linker or a longer linker. A highlight of our findings was the substantial thermostability observed in the serine-rich variant. Importantly, the linker affects thermal unfolding behavior and enzyme stability. In particular, unfolding studies show that the two domains unfold independently when mixed, whereas the full-length enzyme shows one cooperative unfolding transition, meaning that the impact of linkers in biomass-processing enzymes is more complex than mere structural tethering.
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Affiliation(s)
- Zarah Forsberg
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
| | - Anton A Stepnov
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Giulio Tesei
- Structural Biology and NMR Laboratory, Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Yong Wang
- Structural Biology and NMR Laboratory, Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark; College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Edith Buchinger
- Vectron Biosolutions AS, Trondheim, Norway; Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Sandra K Kristiansen
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Finn L Aachmann
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Lise Arleth
- X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory, Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Gaston Courtade
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway.
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Østby H, Christensen IA, Hennum K, Várnai A, Buchinger E, Grandal S, Courtade G, Hegnar OA, Aachmann FL, Eijsink VGH. Functional characterization of a lytic polysaccharide monooxygenase from Schizophyllum commune that degrades non-crystalline substrates. Sci Rep 2023; 13:17373. [PMID: 37833388 PMCID: PMC10575960 DOI: 10.1038/s41598-023-44278-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/05/2023] [Indexed: 10/15/2023] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are mono-copper enzymes that use O2 or H2O2 to oxidatively cleave glycosidic bonds. LPMOs are prevalent in nature, and the functional variation among these enzymes is a topic of great interest. We present the functional characterization of one of the 22 putative AA9-type LPMOs from the fungus Schizophyllum commune, ScLPMO9A. The enzyme, expressed in Escherichia coli, showed C4-oxidative cleavage of amorphous cellulose and soluble cello-oligosaccharides. Activity on xyloglucan, mixed-linkage β-glucan, and glucomannan was also observed, and product profiles differed compared to the well-studied C4-oxidizing NcLPMO9C from Neurospora crassa. While NcLPMO9C is also active on more crystalline forms of cellulose, ScLPMO9A is not. Differences between the two enzymes were also revealed by nuclear magnetic resonance (NMR) titration studies showing that, in contrast to NcLPMO9C, ScLPMO9A has higher affinity for linear substrates compared to branched substrates. Studies of H2O2-fueled degradation of amorphous cellulose showed that ScLPMO9A catalyzes a fast and specific peroxygenase reaction that is at least two orders of magnitude faster than the apparent monooxygenase reaction. Together, these results show that ScLPMO9A is an efficient LPMO with a broad substrate range, which, rather than acting on cellulose, has evolved to act on amorphous and soluble glucans.
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Affiliation(s)
- Heidi Østby
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
| | - Idd A Christensen
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands Vei 6/8, 7491, Trondheim, Norway
| | - Karen Hennum
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
| | - Edith Buchinger
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands Vei 6/8, 7491, Trondheim, Norway
| | - Siri Grandal
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands Vei 6/8, 7491, Trondheim, Norway
| | - Gaston Courtade
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands Vei 6/8, 7491, Trondheim, Norway
| | - Olav A Hegnar
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
| | - Finn L Aachmann
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands Vei 6/8, 7491, Trondheim, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway.
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10
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Dan M, Zheng Y, Zhao G, Hsieh YSY, Wang D. Current insights of factors interfering the stability of lytic polysaccharide monooxygenases. Biotechnol Adv 2023; 67:108216. [PMID: 37473820 DOI: 10.1016/j.biotechadv.2023.108216] [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: 03/20/2023] [Revised: 06/30/2023] [Accepted: 07/16/2023] [Indexed: 07/22/2023]
Abstract
Cellulose and chitin are two of the most abundant biopolymers in nature, but they cannot be effectively utilized in industry due to their recalcitrance. This limitation was overcome by the advent of lytic polysaccharide monooxygenases (LPMOs), which promote the disruption of biopolymers through oxidative mechanism and provide a breakthrough in the action of hydrolytic enzymes. In the application of LPMOs to biomass degradation, the key to consistent and effective functioning lies in their stability. The efficient transformation of biomass resources using LPMOs depends on factors that interfere with their stability. This review discussed three aspects that affect LPMO stability: general external factors, structural factors, and factors in the enzyme-substrate reaction. It explains how these factors impact LPMO stability, discusses the resulting effects, and finally presents relevant measures and considerations, including potential resolutions. The review also provides suggestions for the application of LPMOs in polysaccharide degradation.
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Affiliation(s)
- Meiling Dan
- College of Food Science, Southwest University, Chongqing 400715, China
| | - Yuting Zheng
- College of Food Science, Southwest University, Chongqing 400715, China
| | - Guohua Zhao
- College of Food Science, Southwest University, Chongqing 400715, China
| | - Yves S Y Hsieh
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, AlbaNova University Centre, 106 91 Stockholm, Sweden; School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan.
| | - Damao Wang
- College of Food Science, Southwest University, Chongqing 400715, China.
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11
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Kuusk S, Eijsink VGH, Väljamäe P. The "life-span" of lytic polysaccharide monooxygenases (LPMOs) correlates to the number of turnovers in the reductant peroxidase reaction. J Biol Chem 2023; 299:105094. [PMID: 37507015 PMCID: PMC10458328 DOI: 10.1016/j.jbc.2023.105094] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/02/2023] [Accepted: 07/22/2023] [Indexed: 07/30/2023] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are monocopper enzymes that degrade the insoluble crystalline polysaccharides cellulose and chitin. Besides the H2O2 cosubstrate, the cleavage of glycosidic bonds by LPMOs depends on the presence of a reductant needed to bring the enzyme into its reduced, catalytically active Cu(I) state. Reduced LPMOs that are not bound to substrate catalyze reductant peroxidase reactions, which may lead to oxidative damage and irreversible inactivation of the enzyme. However, the kinetics of this reaction remain largely unknown, as do possible variations between LPMOs belonging to different families. Here, we describe the kinetic characterization of two fungal family AA9 LPMOs, TrAA9A of Trichoderma reesei and NcAA9C of Neurospora crassa, and two bacterial AA10 LPMOs, ScAA10C of Streptomyces coelicolor and SmAA10A of Serratia marcescens. We found peroxidation of ascorbic acid and methyl-hydroquinone resulted in the same probability of LPMO inactivation (pi), suggesting that inactivation is independent of the nature of the reductant. We showed the fungal enzymes were clearly more resistant toward inactivation, having pi values of less than 0.01, whereas the pi for SmAA10A was an order of magnitude higher. However, the fungal enzymes also showed higher catalytic efficiencies (kcat/KM(H2O2)) for the reductant peroxidase reaction. This inverse linear correlation between the kcat/KM(H2O2) and pi suggests that, although having different life spans in terms of the number of turnovers in the reductant peroxidase reaction, LPMOs that are not bound to substrates have similar half-lives. These findings have not only potential biological but also industrial implications.
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Affiliation(s)
- Silja Kuusk
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, NMBU - Norwegian University of Life Sciences, Ås, Norway
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia.
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12
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Hall K, Joseph C, Ayuso-Fernández I, Tamhankar A, Rieder L, Skaali R, Golten O, Neese F, Røhr ÅK, Jannuzzi SAV, DeBeer S, Eijsink VGH, Sørlie M. A Conserved Second Sphere Residue Tunes Copper Site Reactivity in Lytic Polysaccharide Monooxygenases. J Am Chem Soc 2023; 145:18888-18903. [PMID: 37584157 PMCID: PMC10472438 DOI: 10.1021/jacs.3c05342] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Indexed: 08/17/2023]
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are powerful monocopper enzymes that can activate strong C-H bonds through a mechanism that remains largely unknown. Herein, we investigated the role of a conserved glutamine/glutamate in the second coordination sphere. Mutation of the Gln in NcAA9C to Glu, Asp, or Asn showed that the nature and distance of the headgroup to the copper fine-tune LPMO functionality and copper reactivity. The presence of Glu or Asp close to the copper lowered the reduction potential and decreased the ratio between the reduction and reoxidation rates by up to 500-fold. All mutants showed increased enzyme inactivation, likely due to changes in the confinement of radical intermediates, and displayed changes in a protective hole-hopping pathway. Electron paramagnetic resonance (EPR) and X-ray absorption spectroscopic (XAS) studies gave virtually identical results for all NcAA9C variants, showing that the mutations do not directly perturb the Cu(II) ligand field. DFT calculations indicated that the higher experimental reoxidation rate observed for the Glu mutant could be reconciled if this residue is protonated. Further, for the glutamic acid form, we identified a Cu(III)-hydroxide species formed in a single step on the H2O2 splitting path. This is in contrast to the Cu(II)-hydroxide and hydroxyl intermediates, which are predicted for the WT and the unprotonated glutamate variant. These results show that this second sphere residue is a crucial determinant of the catalytic functioning of the copper-binding histidine brace and provide insights that may help in understanding LPMOs and LPMO-inspired synthetic catalysts.
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Affiliation(s)
- Kelsi
R. Hall
- Faculty
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Chris Joseph
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Iván Ayuso-Fernández
- Faculty
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Ashish Tamhankar
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Lukas Rieder
- Institute
for Molecular Biotechnology, Graz University
of Technology, 8010, Graz, Austria
| | - Rannei Skaali
- Faculty
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Ole Golten
- Faculty
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Åsmund K. Røhr
- Faculty
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Sergio A. V. Jannuzzi
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Vincent G. H. Eijsink
- Faculty
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Morten Sørlie
- Faculty
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
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13
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Tuveng TR, Østby H, Tamburrini KC, Bissaro B, Hegnar OA, Stepnov AA, Várnai A, Berrin JG, Eijsink VGH. Revisiting the AA14 family of lytic polysaccharide monooxygenases and their catalytic activity. FEBS Lett 2023; 597:2086-2102. [PMID: 37418595 DOI: 10.1002/1873-3468.14694] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/08/2023] [Accepted: 06/26/2023] [Indexed: 07/09/2023]
Abstract
Lytic polysaccharide monooxygenases (LPMOs) belonging to the AA14 family are believed to contribute to the enzymatic degradation of lignocellulosic biomass by specifically acting on xylan in recalcitrant cellulose-xylan complexes. Functional characterization of an AA14 LPMO from Trichoderma reesei, TrAA14A, and a re-evaluation of the properties of the previously described AA14 from Pycnoporus coccineus, PcoAA14A, showed that these proteins have oxidase and peroxidase activities that are common for LPMOs. However, we were not able to detect activity on cellulose-associated xylan or any other tested polysaccharide substrate, meaning that the substrate of these enzymes remains unknown. Next to raising questions regarding the true nature of AA14 LPMOs, the present data illustrate possible pitfalls in the functional characterization of these intriguing enzymes.
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Affiliation(s)
- Tina R Tuveng
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Heidi Østby
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Ketty C Tamburrini
- INRAE, Aix Marseille Univ, UMR1163 Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Bastien Bissaro
- INRAE, Aix Marseille Univ, UMR1163 Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Olav A Hegnar
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Anton A Stepnov
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Jean-Guy Berrin
- INRAE, Aix Marseille Univ, UMR1163 Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
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14
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Sun P, Huang Z, Banerjee S, Kadowaki MAS, Veersma RJ, Magri S, Hilgers R, Muderspach SJ, Laurent CV, Ludwig R, Cannella D, Lo Leggio L, van Berkel WJH, Kabel MA. AA16 Oxidoreductases Boost Cellulose-Active AA9 Lytic Polysaccharide Monooxygenases from Myceliophthora thermophila. ACS Catal 2023; 13:4454-4467. [PMID: 37066045 PMCID: PMC10088020 DOI: 10.1021/acscatal.3c00874] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/06/2023] [Indexed: 04/18/2023]
Abstract
Copper-dependent lytic polysaccharide monooxygenases (LPMOs) classified in Auxiliary Activity (AA) families are considered indispensable as synergistic partners for cellulolytic enzymes to saccharify recalcitrant lignocellulosic plant biomass. In this study, we characterized two fungal oxidoreductases from the new AA16 family. We found that MtAA16A from Myceliophthora thermophila and AnAA16A from Aspergillus nidulans did not catalyze the oxidative cleavage of oligo- and polysaccharides. Indeed, the MtAA16A crystal structure showed a fairly LPMO-typical histidine brace active site, but the cellulose-acting LPMO-typical flat aromatic surface parallel to the histidine brace region was lacking. Further, we showed that both AA16 proteins are able to oxidize low-molecular-weight reductants to produce H2O2. The oxidase activity of the AA16s substantially boosted cellulose degradation by four AA9 LPMOs from M. thermophila (MtLPMO9s) but not by three AA9 LPMOs from Neurospora crassa (NcLPMO9s). The interplay with MtLPMO9s is explained by the H2O2-producing capability of the AA16s, which, in the presence of cellulose, allows the MtLPMO9s to optimally drive their peroxygenase activity. Replacement of MtAA16A by glucose oxidase (AnGOX) with the same H2O2-producing activity could only achieve less than 50% of the boosting effect achieved by MtAA16A, and earlier MtLPMO9B inactivation (6 h) was observed. To explain these results, we hypothesized that the delivery of AA16-produced H2O2 to the MtLPMO9s is facilitated by protein-protein interaction. Our findings provide new insights into the functions of copper-dependent enzymes and contribute to a further understanding of the interplay of oxidative enzymes within fungal systems to degrade lignocellulose.
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Affiliation(s)
- Peicheng Sun
- Laboratory
of Food Chemistry, Wageningen University
& Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Zhiyu Huang
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Sanchari Banerjee
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Marco A. S. Kadowaki
- PhotoBioCatalysis
Unit (CPBL) and Biomass Transformation Lab (BTL), École Interfacultaire
de Bioingénieurs (EIB), Université
Libre de Bruxelles, Avenue Franklin D. Roosevelt 50, 1050 Bruxelles, Belgium
| | - Romy J. Veersma
- Laboratory
of Food Chemistry, Wageningen University
& Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Silvia Magri
- PhotoBioCatalysis
Unit (CPBL) and Biomass Transformation Lab (BTL), École Interfacultaire
de Bioingénieurs (EIB), Université
Libre de Bruxelles, Avenue Franklin D. Roosevelt 50, 1050 Bruxelles, Belgium
| | - Roelant Hilgers
- Laboratory
of Food Chemistry, Wageningen University
& Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Sebastian J. Muderspach
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Christophe V.F.P. Laurent
- Biocatalysis
and Biosensing Laboratory, Department of Food Science and Technology, University of Natural Resources and Life Sciences
(BOKU), Muthgasse 18, 1190 Vienna, Austria
- Institute
of Molecular Modeling and Simulation, Department of Material Sciences
and Process Engineering, University of Natural
Resources and Life Sciences (BOKU), Muthgasse 18, 1190 Vienna, Austria
| | - Roland Ludwig
- Biocatalysis
and Biosensing Laboratory, Department of Food Science and Technology, University of Natural Resources and Life Sciences
(BOKU), Muthgasse 18, 1190 Vienna, Austria
| | - David Cannella
- PhotoBioCatalysis
Unit (CPBL) and Biomass Transformation Lab (BTL), École Interfacultaire
de Bioingénieurs (EIB), Université
Libre de Bruxelles, Avenue Franklin D. Roosevelt 50, 1050 Bruxelles, Belgium
| | - Leila Lo Leggio
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Willem J. H. van Berkel
- Laboratory
of Food Chemistry, Wageningen University
& Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Mirjam A. Kabel
- Laboratory
of Food Chemistry, Wageningen University
& Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
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15
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Votvik AK, Røhr ÅK, Bissaro B, Stepnov AA, Sørlie M, Eijsink VGH, Forsberg Z. Structural and functional characterization of the catalytic domain of a cell-wall anchored bacterial lytic polysaccharide monooxygenase from Streptomyces coelicolor. Sci Rep 2023; 13:5345. [PMID: 37005446 PMCID: PMC10067821 DOI: 10.1038/s41598-023-32263-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/24/2023] [Indexed: 04/04/2023] Open
Abstract
Bacterial lytic polysaccharide monooxygenases (LPMOs) are known to oxidize the most abundant and recalcitrant polymers in Nature, namely cellulose and chitin. The genome of the model actinomycete Streptomyces coelicolor A3(2) encodes seven putative LPMOs, of which, upon phylogenetic analysis, four group with typical chitin-oxidizing LPMOs, two with typical cellulose-active LPMOs, and one which stands out by being part of a subclade of non-characterized enzymes. The latter enzyme, called ScLPMO10D, and most of the enzymes found in this subclade are unique, not only because of variation in the catalytic domain, but also as their C-terminus contains a cell wall sorting signal (CWSS), which flags the LPMO for covalent anchoring to the cell wall. Here, we have produced a truncated version of ScLPMO10D without the CWSS and determined its crystal structure, EPR spectrum, and various functional properties. While showing several structural and functional features typical for bacterial cellulose active LPMOs, ScLPMO10D is only active on chitin. Comparison with two known chitin-oxidizing LPMOs of different taxa revealed interesting functional differences related to copper reactivity. This study contributes to our understanding of the biological roles of LPMOs and provides a foundation for structural and functional comparison of phylogenetically distant LPMOs with similar substrate specificities.
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Affiliation(s)
- Amanda K Votvik
- Faculty of Chemistry, Biotechnology, and Food Science, The Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Åsmund K Røhr
- Faculty of Chemistry, Biotechnology, and Food Science, The Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Bastien Bissaro
- Faculty of Chemistry, Biotechnology, and Food Science, The Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
- INRAE, Aix Marseille University, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
| | - Anton A Stepnov
- Faculty of Chemistry, Biotechnology, and Food Science, The Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Science, The Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, The Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway
| | - Zarah Forsberg
- Faculty of Chemistry, Biotechnology, and Food Science, The Norwegian University of Life Sciences (NMBU), 1432, Ås, Norway.
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16
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Zhang Y, Pan D, Xiao P, Xu Q, Geng F, Zhang X, Zhou X, Xu H. A novel lytic polysaccharide monooxygenase from enrichment microbiota and its application for shrimp shell powder biodegradation. Front Microbiol 2023; 14:1097492. [PMID: 37007517 PMCID: PMC10057547 DOI: 10.3389/fmicb.2023.1097492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 02/27/2023] [Indexed: 03/17/2023] Open
Abstract
Lytic polysaccharide monooxygenases (LPMO) are expected to change the current status of chitin resource utilization. This study reports that targeted enrichment of the microbiota was performed with chitin by the selective gradient culture technique, and a novel LPMO (M2822) was identified from the enrichment microbiota metagenome. First, soil samples were screened based on soil bacterial species and chitinase biodiversity. Then gradient enrichment culture with different chitin concentrations was carried out. The efficiency of chitin powder degradation was increased by 10.67 times through enrichment, and chitin degradation species Chitiniphilus and Chitinolyticbacter were enriched significantly. A novel LPMO (M2822) was found in the metagenome of the enriched microbiota. Phylogenetic analysis showed that M2822 had a unique phylogenetic position in auxiliary activity (AA) 10 family. The analysis of enzymatic hydrolysate showed that M2822 had chitin activity. When M2822 synergized with commercial chitinase to degrade chitin, the yield of N-acetyl glycosamine was 83.6% higher than chitinase alone. The optimum temperature and pH for M2822 activity were 35°C and 6.0. The synergistic action of M2822 and chitin-degrading enzymes secreted by Chitiniphilus sp. LZ32 could efficiently hydrolyze shrimp shell powder. After 12 h of enzymatic hydrolysis, chitin oligosaccharides (COS) yield reached 4,724 μg/mL. To our knowledge, this work is the first study to mine chitin activity LPMO in the metagenome of enriched microbiota. The obtained M2822 showed application prospects in the efficient production of COS.
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Affiliation(s)
- Yang Zhang
- School of Life Science, Liaocheng University, Liaocheng, Shandong, China
| | - Delong Pan
- School of Life Science, Liaocheng University, Liaocheng, Shandong, China
| | - Peiyao Xiao
- School of Life Science, Liaocheng University, Liaocheng, Shandong, China
| | - Qianqian Xu
- School of Life Science, Liaocheng University, Liaocheng, Shandong, China
| | - Fan Geng
- School of Life Science, Liaocheng University, Liaocheng, Shandong, China
| | - Xinyu Zhang
- School of Life Science, Liaocheng University, Liaocheng, Shandong, China
| | - Xiuling Zhou
- School of Life Science, Liaocheng University, Liaocheng, Shandong, China
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
- *Correspondence: Xiuling Zhou,
| | - Hong Xu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
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17
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Hansen LD, Eijsink VGH, Horn SJ, Várnai A. H 2 O 2 feeding enables LPMO-assisted cellulose saccharification during simultaneous fermentative production of lactic acid. Biotechnol Bioeng 2023; 120:726-736. [PMID: 36471631 DOI: 10.1002/bit.28298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/20/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
Abstract
Simultaneous saccharification and fermentation (SSF) is a well-known strategy for valorization of lignocellulosic biomass. Because the fermentation process typically is anaerobic, oxidative enzymes found in modern commercial cellulase cocktails, such as lytic polysaccharide monooxygenases (LPMOs), may be inhibited, limiting the overall efficiency of the enzymatic saccharification. Recent discoveries, however, have shown that LPMOs are active under anoxic conditions if they are provided with H2 O2 at low concentrations. In this study, we build on this concept and investigate the potential of using externally added H2 O2 to sustain oxidative cellulose depolymerization by LPMOs during an SSF process for lactic acid production. The results of bioreactor experiments with 100 g/L cellulose clearly show that continuous addition of small amounts of H2 O2 (at a rate of 80 µM/h) during SSF enables LPMO activity and improves lactic acid production. While further process optimization is needed, the present proof-of-concept results show that modern LPMO-containing cellulase cocktails such as Cellic CTec2 can be used in SSF setups, without sacrificing the LPMO activity in these cocktails.
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Affiliation(s)
- Line D Hansen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Aas, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Aas, Norway
| | - Svein J Horn
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Aas, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Aas, Norway
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18
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Cordas CM, Valério GN, Stepnov A, Kommedal E, Kjendseth ÅR, Forsberg Z, Eijsink VGH, Moura JJG. Electrochemical characterization of a family AA10 LPMO and the impact of residues shaping the copper site on reactivity. J Inorg Biochem 2023; 238:112056. [PMID: 36332410 DOI: 10.1016/j.jinorgbio.2022.112056] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/09/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022]
Abstract
Research on enzymes for lignocellulose biomass degradation has progressively increased in recent years due to the interest in taking advantage of this natural resource. Among these enzymes are the lytic polysaccharide monooxygenases (LPMOs) that oxidatively depolymerize crystalline cellulose using a reactive oxygen species generated in a reduced mono‑copper active site. The copper site comprises of a highly conserved histidine-brace, providing three equatorial nitrogen ligands, whereas less conserved residues close to the copper contribute to shaping and confining the site. The catalytic copper site is exposed to the solvent and to the crystalline substrates, and as so, the influence of the copper environment on LPMO properties, including the redox potential, is of great interest. In the current work, a direct electrochemical study of an LPMO (ScLPMO10C) was conducted allowing to retrieve kinetic and thermodynamic data associated with the redox transition in the catalytic centre. Moreover, two residues that do not bind to the copper but shape the copper sites were mutated, and the properties of the mutants were compared with those of the wild-type enzyme. The direct electrochemical studies, using cyclic voltammetry, yielded redox potentials in the +200 mV range, well in line with LPMO redox potentials determined by other methods. Interestingly, while the mutations hardly affected the formal redox potential of the enzyme, they drastically affected the reactivity of the copper site and enzyme functionality.
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Affiliation(s)
- Cristina M Cordas
- LAQV, REQUIMTE, NOVA School of Sciences and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal.
| | - Gabriel N Valério
- LAQV, REQUIMTE, NOVA School of Sciences and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
| | - Anton Stepnov
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway
| | - Eirik Kommedal
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway
| | - Åsmund R Kjendseth
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway
| | - Zarah Forsberg
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway.
| | - José J G Moura
- LAQV, REQUIMTE, NOVA School of Sciences and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
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19
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Abstract
Lytic polysaccharide monooxygenases (LPMOs) are unique redox enzymes capable of disrupting the crystalline surfaces of industry-relevant recalcitrant polysaccharides, such as chitin and cellulose. Historically, LPMOs were thought to be slow enzymes relying on O2 as the co-substrate, but it is now clear that these enzymes prefer H2O2, allowing for fast depolymerization of polysaccharides through a peroxygenase reaction. Thus, quantifying H2O2 in LPMO reaction set-ups is of a great interest. The horseradish peroxidase (HRP)/Amplex Red (AR) assay is one of the most popular and accessible tools for measuring hydrogen peroxide. This assay has been used in various types of biological and biochemical studies, including LPMO research, but suffers from pitfalls that need to be accounted for. In this Chapter, we discuss this method and its use for assessing the often rate-limiting in situ formation of H2O2 in LPMO reactions. We show that, after accounting for multiple potential side reactions, quantitative data on H2O2 production obtained with the HRP/Amplex Red assay provide useful clues for understanding the catalytic activity of LPMOs, including the impact of reductants and transition metal ions.
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Affiliation(s)
- Anton A Stepnov
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway.
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20
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On the impact of carbohydrate-binding modules (CBMs) in lytic polysaccharide monooxygenases (LPMOs). Essays Biochem 2022; 67:561-574. [PMID: 36504118 PMCID: PMC10154629 DOI: 10.1042/ebc20220162] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 12/14/2022]
Abstract
Abstract
Lytic polysaccharide monooxygenases (LPMOs) have revolutionized our understanding of how enzymes degrade insoluble polysaccharides. Compared with the substantial knowledge developed on the structure and mode of action of the catalytic LPMO domains, the (multi)modularity of LPMOs has received less attention. The presence of other domains, in particular carbohydrate-binding modules (CBMs), tethered to LPMOs has profound implications for the catalytic performance of the full-length enzymes. In the last few years, studies on LPMO modularity have led to advancements in elucidating how CBMs, other domains, and linker regions influence LPMO structure and function. This mini review summarizes recent literature, with particular focus on comparative truncation studies, to provide an overview of the diversity in LPMO modularity and the functional implications of this diversity.
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21
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Evaluation of Enzymatic Hydrolysis of Sugarcane Bagasse Using Combination of Enzymes or Co-Substrate to Boost Lytic Polysaccharide Monooxygenases Action. Catalysts 2022. [DOI: 10.3390/catal12101158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
This study evaluated innovative approaches for the enzymatic hydrolysis of lignocellulosic biomass. More specifically, assays were performed to evaluate the supplementation of the commercial cellulolytic cocktail Cellic® CTec2 (CC2) with LPMO (GcLPMO9B), H2O2, or cello-oligosaccharide dehydrogenase (CelDH) FgCelDH7C in order to boost the LPMO action and improve the saccharification efficiency of biomass into monosaccharides. The enzymatic hydrolysis was carried out using sugarcane bagasse pretreated by hydrodynamic cavitation-assisted oxidative process, 10% (w/w) solid loading, and 30 FPU CC2/g dry biomass. The results were compared in terms of sugars release and revealed an important influence of the supplementations at the initial 6 h of hydrolysis. While the addition of CelDH led to a steady increase in glucose production to reach 101.1 mg of glucose/g DM, accounting for the highest value achieved after 72 h of hydrolysis, boosting the LPMOs activity by the supplementation of pure LPMOs or the LPMO co-substrate H2O2 were also effective to improve the cellulose conversion, increasing the initial reaction rate of the hydrolysis. These results revealed that LPMOs play an important role on enzymatic hydrolysis of cellulose and boosting their action can help to improve the reaction rate and increase the hydrolysis yield. LPMOs-CelDH oxidative pairs represent a novel potent combination for use in the enzymatic hydrolysis of lignocellulose biomass. Finally, the strategies presented in this study are promising approaches for application in lignocellulosic biorefineries, especially using sugarcane bagasse as a feedstock.
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Structural perturbations of substrate binding and oxidation state changes in a lytic polysaccharide monooxygenase. J Biol Inorg Chem 2022; 27:705-713. [PMID: 36208326 PMCID: PMC9653361 DOI: 10.1007/s00775-022-01966-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 09/20/2022] [Indexed: 01/06/2023]
Abstract
LPMOs are enzymes which catalyse the oxidation of a C-H bond within polysaccharides, leading to their oxidative cleavage. To achieve this, LPMOs employ highly reactive oxidising intermediates, the generation of which is likely coupled to substrate binding to the enzyme. The nature of this coupling is unknown. Here we report a statistical comparison for four three-dimensional structures of an AA9 LPMO crystallised in the same space group but in different oxidation and substrate-binding states, to determine which significant structural perturbations occur at the enzyme upon either oxidation state change or the binding of substrate. In a novel step, we determine the global random error associated with the positional coordinates of atoms using the method of moments to ascertain the statistical estimators of Gaussian distributions of pairwise RMS differences between individual atoms in different structures. The results show that a change in the oxidation state of the copper leads to no significant structural changes, and that binding of the substrate leads to a single change in the conformation of a tryptophan residue. This tryptophan has previously been identified as part of a charge transfer pathway between the active site and the external surface of the protein, and the structural change identified herein may be part of the substrate-enzyme coupling mechanism.
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