1
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Rieder L, Sørlie M. Recent Advances in Understanding LPMO Catalysis. Biochemistry 2023; 62:3170-3172. [PMID: 37916429 PMCID: PMC10666270 DOI: 10.1021/acs.biochem.3c00458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Indexed: 11/03/2023]
Affiliation(s)
- Lukas Rieder
- Institute
of Molecular Biotechnology, Graz University
of Technology, Petersgasse 14, A-8010 Graz, Austria
| | - Morten Sørlie
- Faculty
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Chr. M. Falsensvei 18, N-1432 Ås, Norway
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2
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Hamre AG, Al-Sadawi R, Johannesen KM, Bisarro B, Kjendseth ÅR, Leiros HKS, Sørlie M. Initial characterization of an iron superoxide dismutase from Thermobifida fusca. J Biol Inorg Chem 2023; 28:689-698. [PMID: 37725277 PMCID: PMC10520107 DOI: 10.1007/s00775-023-02019-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 08/24/2023] [Indexed: 09/21/2023]
Abstract
Superoxide dismutases (SODs) are enzymes that catalyze the dismutation of the superoxide radical anion into O2 and H2O2 in a two-step reaction. They are ubiquitous to all forms of life and four different types of metal centers are detected, dividing this class of enzymes into Cu-/Zn-, Ni-, Mn-, and Fe-SODs. In this study, a superoxide dismutase from the thermophilic bacteria Thermobifida fusca (TfSOD) was cloned and expressed before the recombinant enzyme was characterized. The enzyme was found to be active for superoxide dismutation measured by inhibition of cytochrome c oxidation and the inhibition of the autoxidation of pyrogallol. Its pH-optimum was determined to be 7.5, while it has a broad temperature optimum ranging from 20 to 90 °C. Combined with the Tm that was found to be 78.5 ± 0.5 °C at pH 8.0, TfSOD can be defined as a thermostable enzyme. Moreover, the crystal structure of TfSOD was determined and refined to 1.25 Å resolution. With electron paramagnetic resonance spectroscopy, it was confirmed that iron is the metal co-factor of TfSOD. The cell potential (Em) for the TfSOD-Fe3+/TfSOD-Fe2+ redox couple was determined to be 287 mV.
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Affiliation(s)
- Anne Grethe Hamre
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, 1432, Ås, Norway
| | - Rim Al-Sadawi
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, 1432, Ås, Norway
| | - Kirsti Merete Johannesen
- Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, 9037, Tromsö, Norway
| | - Bastien Bisarro
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, 1432, Ås, Norway
| | - Åsmund Røhr Kjendseth
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, 1432, Ås, Norway
| | - Hanna-Kirsti S Leiros
- Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, 9037, Tromsö, Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, 1432, Ås, Norway.
- Department for Physics and Technology, Faculty of Science and Technology, UiT The Arctic University of Norway, 9037, Tromsö, Norway.
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3
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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: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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4
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Golten O, Ayuso-Fernández I, Hall KR, Stepnov AA, Sørlie M, Røhr ÅK, Eijsink VGH. Reductants fuel lytic polysaccharide monooxygenase activity in a pH-dependent manner. FEBS Lett 2023; 597:1363-1374. [PMID: 37081294 DOI: 10.1002/1873-3468.14629] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 04/22/2023]
Abstract
Polysaccharide-degrading mono-copper lytic polysaccharide monooxygenases (LPMOs) are efficient peroxygenases that require electron donors (reductants) to remain in the active Cu(I) form and to generate the H2 O2 co-substrate from molecular oxygen. Here, we show how commonly used reductants affect LPMO catalysis in a pH-dependent manner. Between pH 6.0 and 8.0, reactions with ascorbic acid show little pH-dependency, whereas reactions with gallic acid become much faster at increased pH. These dependencies correlate with the reductant ionization state, which affects its ability to react with molecular oxygen and generate H2 O2 . The correlation does not apply to L-cysteine because, as shown by stopped-flow kinetics, increased H2 O2 production at higher pH is counteracted by increased binding of L-cysteine to the copper active site. The findings highlight the importance of the choice of reductant and pH in LPMO reactions.
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Affiliation(s)
- Ole Golten
- Faculty of Chemistry, Biotechnology and Food Science, NMBU- Norwegian University of Life Sciences, Ås, Norway
| | - Iván Ayuso-Fernández
- Faculty of Chemistry, Biotechnology and Food Science, NMBU- Norwegian University of Life Sciences, Ås, Norway
| | - Kelsi R Hall
- Faculty of Chemistry, Biotechnology and Food Science, NMBU- Norwegian University of Life Sciences, Ås, Norway
| | - Anton A Stepnov
- Faculty of Chemistry, Biotechnology and Food Science, NMBU- Norwegian University of Life Sciences, Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology and Food Science, NMBU- Norwegian University of Life Sciences, Ås, Norway
| | - Åsmund Kjendseth Røhr
- 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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5
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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6
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Chaudhari YB, Várnai A, Sørlie M, Horn SJ, Eijsink VGH. Engineering cellulases for conversion of lignocellulosic biomass. Protein Eng Des Sel 2023; 36:gzad002. [PMID: 36892404 PMCID: PMC10394125 DOI: 10.1093/protein/gzad002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/13/2023] [Accepted: 02/24/2023] [Indexed: 03/10/2023] Open
Abstract
Lignocellulosic biomass is a renewable source of energy, chemicals and materials. Many applications of this resource require the depolymerization of one or more of its polymeric constituents. Efficient enzymatic depolymerization of cellulose to glucose by cellulases and accessory enzymes such as lytic polysaccharide monooxygenases is a prerequisite for economically viable exploitation of this biomass. Microbes produce a remarkably diverse range of cellulases, which consist of glycoside hydrolase (GH) catalytic domains and, although not in all cases, substrate-binding carbohydrate-binding modules (CBMs). As enzymes are a considerable cost factor, there is great interest in finding or engineering improved and robust cellulases, with higher activity and stability, easy expression, and minimal product inhibition. This review addresses relevant engineering targets for cellulases, discusses a few notable cellulase engineering studies of the past decades and provides an overview of recent work in the field.
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Affiliation(s)
- Yogesh B Chaudhari
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Svein J Horn
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
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7
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Rieder L, Stepnov AA, Sørlie M, Eijsink VG. Fast and Specific Peroxygenase Reactions Catalyzed by Fungal Mono-Copper Enzymes. Biochemistry 2021; 60:3633-3643. [PMID: 34738811 PMCID: PMC8638258 DOI: 10.1021/acs.biochem.1c00407] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 10/27/2021] [Indexed: 11/28/2022]
Abstract
The copper-dependent lytic polysaccharide monooxygenases (LPMOs) are receiving attention because of their role in the degradation of recalcitrant biomass and their intriguing catalytic properties. The fundamentals of LPMO catalysis remain somewhat enigmatic as the LPMO reaction is affected by a multitude of LPMO- and co-substrate-mediated (side) reactions that result in a complex reaction network. We have performed kinetic studies with two LPMOs that are active on soluble substrates, NcAA9C and LsAA9A, using various reductants typically employed for LPMO activation. Studies with NcAA9C under "monooxygenase" conditions showed that the impact of the reductant on catalytic activity is correlated with the hydrogen peroxide-generating ability of the LPMO-reductant combination, supporting the idea that a peroxygenase reaction is taking place. Indeed, the apparent monooxygenase reaction could be inhibited by a competing H2O2-consuming enzyme. Interestingly, these fungal AA9-type LPMOs were found to have higher oxidase activity than bacterial AA10-type LPMOs. Kinetic analysis of the peroxygenase activity of NcAA9C on cellopentaose revealed a fast stoichiometric conversion of high amounts of H2O2 to oxidized carbohydrate products. A kcat value of 124 ± 27 s-1 at 4 °C is 20 times higher than a previously described kcat for peroxygenase activity on an insoluble substrate (at 25 °C) and some 4 orders of magnitude higher than typical "monooxygenase" rates. Similar studies with LsAA9A revealed differences between the two enzymes but confirmed fast and specific peroxygenase activity. These results show that the catalytic site arrangement of LPMOs provides a unique scaffold for highly efficient copper redox catalysis.
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Affiliation(s)
- Lukas Rieder
- Faculty of Chemistry, Biotechnology,
and Food Sciences, Norwegian University
of Life Sciences (NMBU), P.O. Box 5003,
NO, 1432 Ås, Norway
| | - Anton A. Stepnov
- Faculty of Chemistry, Biotechnology,
and Food Sciences, Norwegian University
of Life Sciences (NMBU), P.O. Box 5003,
NO, 1432 Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology,
and Food Sciences, Norwegian University
of Life Sciences (NMBU), P.O. Box 5003,
NO, 1432 Ås, Norway
| | - Vincent G.H. Eijsink
- Faculty of Chemistry, Biotechnology,
and Food Sciences, Norwegian University
of Life Sciences (NMBU), P.O. Box 5003,
NO, 1432 Ås, Norway
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8
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Rieder L, Petrović D, Väljamäe P, Eijsink VG, Sørlie M. Kinetic Characterization of a Putatively Chitin-Active LPMO Reveals a Preference for Soluble Substrates and Absence of Monooxygenase Activity. ACS Catal 2021; 11:11685-11695. [PMID: 34567832 PMCID: PMC8453653 DOI: 10.1021/acscatal.1c03344] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/24/2021] [Indexed: 12/23/2022]
Abstract
![]()
Enzymes known as
lytic polysaccharide monooxygenases (LPMOs) are
recognized as important contributors to aerobic enzymatic degradation
of recalcitrant polysaccharides such as chitin and cellulose. LPMOs
are remarkably abundant in nature, with some fungal species possessing
more than 50 LPMO genes, and the biological implications of this diversity
remain enigmatic. For example, chitin-active LPMOs have been encountered
in biological niches where chitin conversion does not seem to take
place. We have carried out an in-depth kinetic characterization of
a putatively chitin-active LPMO from Aspergillus fumigatus (AfAA11B), which, as we show here, has multiple
unusual properties, such as a low redox potential and high oxidase
activity. Furthermore, AfAA11B is hardly active on
chitin, while being very active on soluble oligomers of N-acetylglucosamine. In the presence of chitotetraose, the enzyme
can withstand considerable amounts of H2O2,
which it uses to efficiently and stoichiometrically convert this substrate.
The unique properties of AfAA11B allowed experiments
showing that it is a strict peroxygenase and does not catalyze a monooxygenase
reaction. This study shows that nature uses LPMOs for breaking glycosidic
bonds in non-polymeric substrates in reactions that depend on H2O2. The quest for the true substrates of these
enzymes, possibly carbohydrates in the cell wall of the fungus or
its competitors, will be of major interest.
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Affiliation(s)
- Lukas Rieder
- Faculty of Chemistry, Biotechnology, and Food Sciences, Norwegian University of Life Sciences (NMBU), Ås N-1432, Norway
| | - Dejan Petrović
- Faculty of Chemistry, Biotechnology, and Food Sciences, Norwegian University of Life Sciences (NMBU), Ås N-1432, Norway
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 50090, Estonia
| | - Vincent G.H. Eijsink
- Faculty of Chemistry, Biotechnology, and Food Sciences, Norwegian University of Life Sciences (NMBU), Ås N-1432, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Sciences, Norwegian University of Life Sciences (NMBU), Ås N-1432, Norway
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9
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Ganan M, Lorentzen SB, Gaustad P, Sørlie M. Synergistic Antifungal Activity of Chito-Oligosaccharides and Commercial Antifungals on Biofilms of Clinical Candida Isolates. J Fungi (Basel) 2021; 7:718. [PMID: 34575756 PMCID: PMC8464920 DOI: 10.3390/jof7090718] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/11/2021] [Accepted: 08/27/2021] [Indexed: 01/09/2023] Open
Abstract
The development of yeast biofilms is a major problem due to their increased antifungal resistance, which leads to persistent infections with severe clinical implications. The high antifungal activity of well-characterized chitosan polymers makes them potential alternatives for treating yeast biofilms. The activity of a chito-oligosaccharide with a depolymerization degree (DPn) of 32 (C32) and a fraction of acetylation (FA) of 0.15 on Candida sp. biofilms was studied. The results showed a concentration-dependent reduction in the number of viable cells present in C. albicans, C. glabrata, and C. guillermondii preformed biofilms in the presence of C32, especially on intermediate and mature biofilms. A significant decrease in the metabolic activity of yeast biofilms treated with C32 was also observed. The antifungals fluconazole (Flu) and miconazole (Mcz) decreased the number of viable cells in preformed early biofilms, but not in the intermediate or mature biofilms. Contrary to Flu or Mcz, C32 also reduced the formation of new biofilms. Interestingly, a synergistic effect on yeast biofilm was observed when C32 and Flu/Mcz were used in combination. C32 has the potential to become an alternative therapeutic agent against Candida biofilms alone or in combination with antifungal drugs and this will reduce the use of antifungals and decrease antifungal resistance.
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Affiliation(s)
- Monica Ganan
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Aas, Norway; (M.G.); (S.B.L.)
- Department of Microbiology, Institute of Clinical Medicine, University of Oslo and Fürst Medical Laboratory, 0154 Oslo, Norway;
| | - Silje B. Lorentzen
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Aas, Norway; (M.G.); (S.B.L.)
| | - Peter Gaustad
- Department of Microbiology, Institute of Clinical Medicine, University of Oslo and Fürst Medical Laboratory, 0154 Oslo, Norway;
| | - Morten Sørlie
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Aas, Norway; (M.G.); (S.B.L.)
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10
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Lorentzen SB, Arntzen MØ, Hahn T, Tuveng TR, Sørlie M, Zibek S, Vaaje-Kolstad G, Eijsink VGH. Genomic and Proteomic Study of Andreprevotia ripae Isolated from an Anthill Reveals an Extensive Repertoire of Chitinolytic Enzymes. J Proteome Res 2021; 20:4041-4052. [PMID: 34191517 PMCID: PMC8802321 DOI: 10.1021/acs.jproteome.1c00358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Chitin is an abundant natural polysaccharide
that is hard to degrade
because of its crystalline nature and because it is embedded in robust
co-polymeric materials containing other polysaccharides, proteins,
and minerals. Thus, it is of interest to study the enzymatic machineries
of specialized microbes found in chitin-rich environments. We describe
a genomic and proteomic analysis of Andreprevotia ripae, a chitinolytic Gram-negative bacterium isolated from an anthill.
The genome of A. ripae encodes four secreted
family GH19 chitinases of which two were detected and upregulated
during growth on chitin. In addition, the genome encodes as many as
25 secreted GH18 chitinases, of which 17 were detected and 12 were
upregulated during growth on chitin. Finally, the single lytic polysaccharide
monooxygenase (LPMO) was strongly upregulated during growth on chitin.
Whereas 66% of the 29 secreted chitinases contained two carbohydrate-binding
modules (CBMs), this fraction was 93% (13 out of 14) for the upregulated
chitinases, suggesting an important role for these CBMs. Next to an
unprecedented multiplicity of upregulated chitinases, this study reveals
several chitin-induced proteins that contain chitin-binding CBMs but
lack a known catalytic function. These proteins are interesting targets
for discovery of enzymes used by nature to convert chitin-rich biomass.
The MS proteomic data have been deposited in the PRIDE database with
accession number PXD025087.
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Affiliation(s)
- Silje B Lorentzen
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
| | - Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
| | - Thomas Hahn
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Nobelstraße 12, 70569 Stuttgart, Germany
| | - Tina R Tuveng
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
| | - Susanne Zibek
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Nobelstraße 12, 70569 Stuttgart, Germany
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
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11
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Rieder L, Ebner K, Glieder A, Sørlie M. Novel molecular biological tools for the efficient expression of fungal lytic polysaccharide monooxygenases in Pichia pastoris. Biotechnol Biofuels 2021; 14:122. [PMID: 34044872 PMCID: PMC8161572 DOI: 10.1186/s13068-021-01971-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 05/13/2021] [Indexed: 05/13/2023]
Abstract
BACKGROUND Lytic polysaccharide monooxygenases (LPMOs) are attracting large attention due their ability to degrade recalcitrant polysaccharides in biomass conversion and to perform powerful redox chemistry. RESULTS We have established a universal Pichia pastoris platform for the expression of fungal LPMOs using state-of-the-art recombination cloning and modern molecular biological tools to achieve high yields from shake-flask cultivation and simple tag-less single-step purification. Yields are very favorable with up to 42 mg per liter medium for four different LPMOs spanning three different families. Moreover, we report for the first time of a yeast-originating signal peptide from the dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit 1 (OST1) form S. cerevisiae efficiently secreting and successfully processes the N-terminus of LPMOs yielding in fully functional enzymes. CONCLUSION The work demonstrates that the industrially most relevant expression host P. pastoris can be used to express fungal LPMOs from different families in high yields and inherent purity. The presented protocols are standardized and require little equipment with an additional advantage with short cultivation periods.
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Affiliation(s)
- Lukas Rieder
- Faculty of Chemistry, Biotechnology, and Food Sciences, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | | | - Anton Glieder
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, Graz, Austria
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Sciences, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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12
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Stepnov AA, Forsberg Z, Sørlie M, Nguyen GS, Wentzel A, Røhr ÅK, Eijsink VGH. Unraveling the roles of the reductant and free copper ions in LPMO kinetics. Biotechnol Biofuels 2021; 14:28. [PMID: 33478537 PMCID: PMC7818938 DOI: 10.1186/s13068-021-01879-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 01/07/2021] [Indexed: 05/02/2023]
Abstract
BACKGROUND Lytic polysaccharide monooxygenases (LPMOs) are monocopper enzymes that catalyze oxidative depolymerization of industrially relevant crystalline polysaccharides, such as cellulose, in a reaction that depends on an electron donor and O2 or H2O2. While it is well known that LPMOs can utilize a wide variety of electron donors, the variation in reported efficiencies of various LPMO-reductant combinations remains largely unexplained. RESULTS In this study, we describe a novel two-domain cellulose-active family AA10 LPMO from a marine actinomycete, which we have used to look more closely at the effects of the reductant and copper ions on the LPMO reaction. Our results show that ascorbate-driven LPMO reactions are extremely sensitive to very low amounts (micromolar concentrations) of free copper because reduction of free Cu(II) ions by ascorbic acid leads to formation of H2O2, which speeds up the LPMO reaction. In contrast, the use of gallic acid yields steady reactions that are almost insensitive to the presence of free copper ions. Various experiments, including dose-response studies with the enzyme, showed that under typically used reaction conditions, the rate of the reaction is limited by LPMO-independent formation of H2O2 resulting from oxidation of the reductant. CONCLUSION The strong impact of low amounts of free copper on LPMO reactions with ascorbic acid and O2, i.e. the most commonly used conditions when assessing LPMO activity, likely explains reported variations in LPMO rates. The observed differences between ascorbic acid and gallic acid show a way of making LPMO reactions less copper-dependent and illustrate that reductant effects on LPMO action need to be interpreted with great caution. In clean reactions, with minimized generation of H2O2, the (O2-driven) LPMO reaction is exceedingly slow, compared to the much faster peroxygenase reaction that occurs when adding H2O2.
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Affiliation(s)
- Anton A Stepnov
- 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
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway
| | - Giang-Son Nguyen
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | - Alexander Wentzel
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | - Åsmund K Røhr
- 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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13
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Harmsen RAG, Aam BB, Madhuprakash J, Hamre AG, Goddard-Borger ED, Withers SG, Eijsink VGH, Sørlie M. Chemoenzymatic Synthesis of Chito-oligosaccharides with Alternating N-d-Acetylglucosamine and d-Glucosamine. Biochemistry 2020; 59:4581-4590. [DOI: 10.1021/acs.biochem.0c00839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rianne A. G. Harmsen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Berit Bjugan Aam
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Jogi Madhuprakash
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Anne Grethe Hamre
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Ethan D. Goddard-Borger
- Walter & Eliza Hall, Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Department of Chemistry, University of British Colombia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Stephen G. Withers
- Department of Chemistry, University of British Colombia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Vincent G. H. Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
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14
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Courtade G, Ciano L, Paradisi A, Lindley PJ, Forsberg Z, Sørlie M, Wimmer R, Davies GJ, Eijsink VGH, Walton PH, Aachmann FL. Mechanistic basis of substrate-O 2 coupling within a chitin-active lytic polysaccharide monooxygenase: An integrated NMR/EPR study. Proc Natl Acad Sci U S A 2020; 117:19178-19189. [PMID: 32723819 PMCID: PMC7431007 DOI: 10.1073/pnas.2004277117] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) have a unique ability to activate molecular oxygen for subsequent oxidative cleavage of glycosidic bonds. To provide insight into the mode of action of these industrially important enzymes, we have performed an integrated NMR/electron paramagnetic resonance (EPR) study into the detailed aspects of an AA10 LPMO-substrate interaction. Using NMR spectroscopy, we have elucidated the solution-phase structure of apo-BlLPMO10A from Bacillus licheniformis, along with solution-phase structural characterization of the Cu(I)-LPMO, showing that the presence of the metal has minimal effects on the overall protein structure. We have, moreover, used paramagnetic relaxation enhancement (PRE) to characterize Cu(II)-LPMO by NMR spectroscopy. In addition, a multifrequency continuous-wave (CW)-EPR and 15N-HYSCORE spectroscopy study on the uniformly isotope-labeled 63Cu(II)-bound 15N-BlLPMO10A along with its natural abundance isotopologue determined copper spin-Hamiltonian parameters for LPMOs to markedly improved accuracy. The data demonstrate that large changes in the Cu(II) spin-Hamiltonian parameters are induced upon binding of the substrate. These changes arise from a rearrangement of the copper coordination sphere from a five-coordinate distorted square pyramid to one which is four-coordinate near-square planar. There is also a small reduction in metal-ligand covalency and an attendant increase in the d(x2-y2) character/energy of the singly occupied molecular orbital (SOMO), which we propose from density functional theory (DFT) calculations predisposes the copper active site for the formation of a stable Cu-O2 intermediate. This switch in orbital character upon addition of chitin provides a basis for understanding the coupling of substrate binding with O2 activation in chitin-active AA10 LPMOs.
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Affiliation(s)
- Gaston Courtade
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Luisa Ciano
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
- School of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom
- Photon Science Institute, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Alessandro Paradisi
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Peter J Lindley
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Zarah Forsberg
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Reinhard Wimmer
- Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg Ø, Denmark
| | - Gideon J Davies
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Paul H Walton
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom;
| | - Finn L Aachmann
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, Norwegian University of Science and Technology, N-7491 Trondheim, Norway;
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15
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Madhuprakash J, Rani TS, Podile AR, Eijsink VGH, Sørlie M. Thermodynamic insights into the role of aromatic residues in chitooligosaccharide binding to the transglycosylating chitinase-D from Serratia proteamaculans. Biochim Biophys Acta Proteins Proteom 2020; 1868:140414. [PMID: 32224199 DOI: 10.1016/j.bbapap.2020.140414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/17/2020] [Accepted: 03/19/2020] [Indexed: 06/10/2023]
Affiliation(s)
- Jogi Madhuprakash
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway; Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India.
| | - T Swaroopa Rani
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Appa Rao Podile
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway.
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16
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Sørlie M, Horn SJ, Vaaje-Kolstad G, Eijsink VG. Using chitosan to understand chitinases and the role of processivity in the degradation of recalcitrant polysaccharides. REACT FUNCT POLYM 2020. [DOI: 10.1016/j.reactfunctpolym.2020.104488] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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17
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Hamre AG, Sørlie M. Kinetic relationships with processivity in Serratia marcescens family 18 glycoside hydrolases. Biochem Biophys Res Commun 2020; 521:120-124. [PMID: 31629467 DOI: 10.1016/j.bbrc.2019.10.089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 10/10/2019] [Indexed: 10/25/2022]
Abstract
In nature, recalcitrant polysaccharides such as chitin and cellulose are degraded by glycoside hydrolases (GH) that act synergistically through different modes of action including attack from reducing-end and nonreducing-end (exo-mode) and random (endo-mode) on single polysaccharide chains. Both modes can be combined with a processive mechanism where the GH remain bound to the polysaccharide to perform multiple catalytic steps before dissociation into the solution. In this work, we have determined association rate constants and their activation paramaters for three co-evolved GHs from Serratia marcescens (SmChiA, SmChiB, and SmChiC) with an oligomeric substrate. Interestingly, we observe a positive correlation between the association rate constants and processive ability for the GHs. Previously, a positive correlation has been observed between substrate binding affinity and processive ability. SmChiA with highest processive ability of the three GHs bind with a kon of 11.5 ± 0.2 μM-1s-1, which is five-fold and 130-fold faster than SmChiB (less processive) and SmChiC (nonprocessive), respectively.
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Affiliation(s)
- Anne Grethe Hamre
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway.
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18
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Madland E, Crasson O, Vandevenne M, Sørlie M, Aachmann FL. NMR and Fluorescence Spectroscopies Reveal the Preorganized Binding Site in Family 14 Carbohydrate-Binding Module from Human Chitotriosidase. ACS Omega 2019; 4:21975-21984. [PMID: 31891077 PMCID: PMC6933781 DOI: 10.1021/acsomega.9b03043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/26/2019] [Indexed: 05/02/2023]
Abstract
Carbohydrate-binding modules (CBM) play important roles in targeting and increasing the concentration of carbohydrate active enzymes on their substrates. Using NMR to get the solution structure of CBM14, we can gain insight into secondary structure elements and intramolecular interactions with our assigned nuclear overhauser effect peaks. This reveals that two conserved aromatic residues (Phe437 and Phe456) make up the hydrophobic core of the CBM. These residues are also responsible for connecting the two β-sheets together, by being part of β2 and β4, respectively, and together with disulfide bridges, they create CBM14's characteristic "hevein-like" fold. Most CBMs rely on aromatic residues for substrate binding; however, CBM14 contains just a single tryptophan (Trp465) that together with Asn466 enables substrate binding. Interestingly, an alanine mutation of a single residue (Leu454) located behind Trp465 renders the CBM incapable of binding. Fluorescence spectroscopy performed on this mutant reveals a significant blue shift, as well as a minor blue shift for its neighbor Val455. The reduction in steric hindrance causes the tryptophan to be buried into the hydrophobic core of the structure and therefore suggests a preorganized binding site for this CBM. Our results show that both Trp465 and Asn466 are affected when CBM14 interacts with both (GlcNAc)3 and β-chitin, that the binding interactions are weak, and that CBM14 displays a slightly higher affinity toward β-chitin.
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Affiliation(s)
- Eva Madland
- Department
of Biotechnology and Food Science, Norwegian Biopolymer Laboratory
(NOBIPOL), NTNU Norwegian University of
Science and Technology, Trondheim 7491, Norway
| | - Oscar Crasson
- InBioS—Center
for Protein Engineering, Institut de Chimie B6a, Université de Liège, Sart-Tilman, Liège 4000, Belgium
| | - Maryléne Vandevenne
- InBioS—Center
for Protein Engineering, Institut de Chimie B6a, Université de Liège, Sart-Tilman, Liège 4000, Belgium
| | - Morten Sørlie
- Department
of Chemistry, Biotechnology and Food Science, NMBU Norwegian University of Life Sciences, Ås 1430, Norway
| | - Finn L. Aachmann
- Department
of Biotechnology and Food Science, Norwegian Biopolymer Laboratory
(NOBIPOL), NTNU Norwegian University of
Science and Technology, Trondheim 7491, Norway
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19
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Forsberg Z, Sørlie M, Petrović D, Courtade G, Aachmann FL, Vaaje-Kolstad G, Bissaro B, Røhr ÅK, Eijsink VGH. Polysaccharide degradation by lytic polysaccharide monooxygenases. Curr Opin Struct Biol 2019; 59:54-64. [DOI: 10.1016/j.sbi.2019.02.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/22/2019] [Accepted: 02/28/2019] [Indexed: 12/22/2022]
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20
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Jana S, Hamre AG, Eijsink VGH, Sørlie M, Payne CM. Polar residues lining the binding cleft of a Serratia marcescens family 18 chitinase position the substrate for attack and stabilize associative interactions. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1657600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Suvamay Jana
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Anne Grethe Hamre
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Vincent G. H. Eijsink
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Christina M. Payne
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
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21
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Petrović DM, Bissaro B, Chylenski P, Skaugen M, Sørlie M, Jensen MS, Aachmann FL, Courtade G, Várnai A, Eijsink VGH. Methylation of the N-terminal histidine protects a lytic polysaccharide monooxygenase from auto-oxidative inactivation. Protein Sci 2019; 27:1636-1650. [PMID: 29971843 DOI: 10.1002/pro.3451] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/01/2018] [Accepted: 06/04/2018] [Indexed: 12/29/2022]
Abstract
The catalytically crucial N-terminal histidine (His1) of fungal lytic polysaccharide monooxygenases (LPMOs) is post-translationally modified to carry a methylation. The functional role of this methylation remains unknown. We have carried out an in-depth functional comparison of two variants of a family AA9 LPMO from Thermoascus aurantiacus (TaLPMO9A), one with, and one without the methylation on His1. Various activity assays showed that the two enzyme variants are identical in terms of substrate preferences, cleavage specificities and the ability to activate molecular oxygen. During the course of this work, new functional features of TaLPMO9A were discovered, in particular the ability to cleave xyloglucan, and these features were identical for both variants. Using a variety of techniques, we further found that methylation has minimal effects on the pKa of His1, the affinity for copper and the redox potential of bound copper. The two LPMOs did, however, show clear differences in their resistance against oxidative damage. Studies with added hydrogen peroxide confirmed recent claims that low concentrations of H2 O2 boost LPMO activity, whereas excess H2 O2 leads to LPMO inactivation. The methylated variant of TaLPMO9A, produced in Aspergillus oryzae, was more resistant to excess H2 O2 and showed better process performance when using conditions that promote generation of reactive-oxygen species. LPMOs need to protect themselves from reactive oxygen species generated in their active sites and this study shows that methylation of the fully conserved N-terminal histidine provides such protection.
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Affiliation(s)
- Dejan M Petrović
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Bastien Bissaro
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Piotr Chylenski
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Morten Skaugen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Marianne S Jensen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Finn L Aachmann
- Department of Biotechnology and Food Science, NOBIPOL, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Gaston Courtade
- Department of Biotechnology and Food Science, NOBIPOL, Norwegian University of Science and Technology (NTNU), Trondheim, 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
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22
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Chylenski P, Bissaro B, Sørlie M, Røhr ÅK, Várnai A, Horn SJ, Eijsink VG. Lytic Polysaccharide Monooxygenases in Enzymatic Processing of Lignocellulosic Biomass. ACS Catal 2019. [DOI: 10.1021/acscatal.9b00246] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Piotr Chylenski
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Bastien Bissaro
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Åsmund K. Røhr
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Svein J. Horn
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Vincent G.H. Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
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23
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Hamre AG, Kaupang A, Payne CM, Väljamäe P, Sørlie M. Thermodynamic Signatures of Substrate Binding for Three Thermobifida fusca Cellulases with Different Modes of Action. Biochemistry 2019; 58:1648-1659. [PMID: 30785271 DOI: 10.1021/acs.biochem.9b00014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The enzymatic breakdown of recalcitrant polysaccharides is achieved by synergistic enzyme cocktails of glycoside hydrolases (GHs) and accessory enzymes. Many GHs are processive, meaning that they stay bound to the substrate between subsequent catalytic interactions. Cellulases are GHs that catalyze the hydrolysis of cellulose [β-1,4-linked glucose (Glc)]. Here, we have determined the relative subsite binding affinity for a glucose moiety as well as the thermodynamic signatures for (Glc)6 binding to three of the seven cellulases produced by the bacterium Thermobifida fusca. TfCel48A is exo-processive, TfCel9A endo-processive, and TfCel5A endo-nonprocessive. Initial hydrolysis of (Glc)5 and (Glc)6 was performed in H218O enabling the incorporation of an 18O atom at the new reducing end anomeric carbon. A matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of the products reveals the intensity ratios of otherwise identical 18O- and 16O-containing products to provide insight into how the substrate is placed during productive binding. The two processive cellulases have significant binding affinity in subsites where products dissociate during processive hydrolysis, aligned with a need to have a pushing potential to remove obstacles on the substrate. Moreover, we observed a correlation between processive ability and favorable binding free energy, as previously postulated. Upon ligand binding, the largest contribution to the binding free energy is desolvation for all three cellulases as determined by isothermal titration calorimetry. The two endo-active cellulases show a more favorable solvation entropy change compared to the exo-active cellulase, while the two processive cellulases have less favorable changes in binding enthalpy compared to the nonprocessive TfCel5A.
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Affiliation(s)
- Anne Grethe Hamre
- Department of Chemistry, Biotechnology and Food Science , Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
| | - Anita Kaupang
- Department of Chemistry, Biotechnology and Food Science , Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
| | - Christina M Payne
- Department of Chemical and Materials Engineering , University of Kentucky , 177 F. Paul Anderson Tower , Lexington , Kentucky 40506 , United States
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology , University of Tartu , 50090 Tartu , Estonia
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science , Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
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24
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Madhuprakash J, Dalhus B, Vaaje-Kolstad G, Sakuda S, Podile AR, Eijsink VGH, Sørlie M. Structural and Thermodynamic Signatures of Ligand Binding to the Enigmatic Chitinase D of Serratia proteamaculans. J Phys Chem B 2019; 123:2270-2279. [PMID: 30789732 DOI: 10.1021/acs.jpcb.8b11448] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Gram-negative bacteria Serratia marcescens and Serratia proteamaculans have efficient chitinolytic machineries that degrade chitin into N-acetylglucosamine (GlcNAc), which is used as a carbon and energy source. The enzymatic degradation of chitin in these bacteria occurs through the synergistic action of glycoside hydrolases (GHs) that have complementary activities; an endo-acting GH (ChiC) making random scissions on the polysaccharide chains and two exo-acting GHs mainly targeting single reducing (ChiA) and nonreducing (ChiB) chain ends. Both bacteria produce low amounts of a fourth GH18 (ChiD) with an unclear role in chitin degradation. Here, we have determined the thermodynamic signatures for binding of (GlcNAc)6 and the inhibitor allosamidin to SpChiD as well as the crystal structure of SpChiD in complex with allosamidin. The binding free energies for the two ligands are similar (Δ Gr° = -8.9 ± 0.1 and -8.4 ± 0.1 kcal/mol, respectively) with clear enthalpic penalties (Δ Hr° = 3.2 ± 0.1 and 1.8 ± 0.1 kcal/mol, respectively). Binding of (GlcNAc)6 is dominated by solvation entropy change (- TΔ Ssolv° = -17.4 ± 0.4 kcal/mol) and the conformational entropy change dominates for allosamidin binding (- TΔ Sconf° = -9.0 ± 0.2 kcal/mol). These signatures as well as the interactions with allosamidin are very similar to those of SmChiB suggesting that both enzymes are nonreducing end-specific.
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Affiliation(s)
- Jogi Madhuprakash
- Department of Chemistry, Biotechnology and Food Science , NMBU-Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway.,Department of Plant Sciences, School of Life Sciences , University of Hyderabad , Gachibowli, 500046 Hyderabad , India
| | - Bjørn Dalhus
- Department of Medical Biochemistry, Institute for Clinical Medicine , University of Oslo , P.O. Box 4950, Nydalen, N-0424 Oslo , Norway.,Department of Microbiology, Clinic for Laboratory Medicine , Oslo University Hospital, Rikshospitalet , P.O. Box 4950, Nydalen, N-0424 Oslo , Norway
| | - Gustav Vaaje-Kolstad
- Department of Chemistry, Biotechnology and Food Science , NMBU-Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
| | - Shohei Sakuda
- Department of Applied Biological Chemistry , University of Tokyo , Bunkyo-Ku, 113 Tokyo , Japan
| | - Appa Rao Podile
- Department of Plant Sciences, School of Life Sciences , University of Hyderabad , Gachibowli, 500046 Hyderabad , India
| | - Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science , NMBU-Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science , NMBU-Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
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Hamre AG, Strømnes AGS, Gustavsen D, Vaaje-Kolstad G, Eijsink VG, Sørlie M. Treatment of recalcitrant crystalline polysaccharides with lytic polysaccharide monooxygenase relieves the need for glycoside hydrolase processivity. Carbohydr Res 2019; 473:66-71. [DOI: 10.1016/j.carres.2019.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 12/05/2018] [Accepted: 01/05/2019] [Indexed: 11/28/2022]
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26
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Ganan M, Lorentzen SB, Agger JW, Heyward CA, Bakke O, Knutsen SH, Aam BB, Eijsink VGH, Gaustad P, Sørlie M. Antifungal activity of well-defined chito-oligosaccharide preparations against medically relevant yeasts. PLoS One 2019; 14:e0210208. [PMID: 30620751 PMCID: PMC6324834 DOI: 10.1371/journal.pone.0210208] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/18/2018] [Indexed: 11/19/2022] Open
Abstract
Due to their antifungal activity, chitosan and its derivatives have potential to be used for treating yeast infections in humans. However, to be considered for use in human medicine, it is necessary to control and know the chemical composition of the compound, which is not always the case for polymeric chitosans. Here, we analyze the antifungal activity of a soluble and well-defined chito-oligosaccharide (CHOS) with an average polymerization degree (DPn) of 32 and fraction of acetylation (FA) of 0.15 (C32) on 52 medically relevant yeast strains. Minimal inhibitory concentrations (MIC) varied widely among yeast species, strains and isolates (from > 5000 to < 9.77 μg mL-1) and inhibition patterns showed a time- and dose-dependencies. The antifungal activity was predominantly fungicidal and was inversely proportional to the pH, being maximal at pH 4.5, the lowest tested pH. Furthermore, antifungal effects of CHOS fractions with varying average molecular weight indicated that those fractions with an intermediate degree of polymerization, i.e. DP 31 and 54, had the strongest inhibitory effects. Confocal imaging showed that C32 adsorbs to the cell surface, with subsequent cell disruption and accumulation of C32 in the cytoplasm. Thus, C32 has potential to be used as a therapy for fungal infections.
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Affiliation(s)
- Monica Ganan
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Aas, Norway
- Institute of Clinical Medicine, Department of Microbiology, University of Oslo, Blindern, Oslo, Norway
| | - Silje B. Lorentzen
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | - Jane W. Agger
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | | | - Oddmund Bakke
- Department of Biosciences, University of Oslo, Blindern, Oslo, Norway
| | - Svein H. Knutsen
- Nofima, Norwegian Institute of Food Fisheries & Aquaculture Research, Aas, Norway
| | - Berit B. Aam
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | - Vincent G. H. Eijsink
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | - Peter Gaustad
- Institute of Clinical Medicine, Department of Microbiology, University of Oslo, Blindern, Oslo, Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Aas, Norway
- * E-mail:
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Kuusk S, Kont R, Kuusk P, Heering A, Sørlie M, Bissaro B, Eijsink VGH, Väljamäe P. Kinetic insights into the role of the reductant in H 2O 2-driven degradation of chitin by a bacterial lytic polysaccharide monooxygenase. J Biol Chem 2018; 294:1516-1528. [PMID: 30514757 DOI: 10.1074/jbc.ra118.006196] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/23/2018] [Indexed: 12/13/2022] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are monocopper enzymes that catalyze oxidative cleavage of glycosidic bonds in polysaccharides in the presence of an external electron donor (reductant). In the classical O2-driven monooxygenase reaction, the reductant is needed in stoichiometric amounts. In a recently discovered, more efficient H2O2-driven reaction, the reductant would be needed only for the initial reduction (priming) of the LPMO to its catalytically active Cu(I) form. However, the influence of the reductant on reducing the LPMO or on H2O2 production in the reaction remains undefined. Here, we conducted a detailed kinetic characterization to investigate how the reductant affects H2O2-driven degradation of 14C-labeled chitin by a bacterial LPMO, SmLPMO10A (formerly CBP21). Sensitive detection of 14C-labeled products and careful experimental set-ups enabled discrimination between the effects of the reductant on LPMO priming and other effects, in particular enzyme-independent production of H2O2 through reactions with O2 When supplied with H2O2, SmLPMO10A catalyzed 18 oxidative cleavages per molecule of ascorbic acid, suggesting a "priming reduction" reaction. The dependence of initial rates of chitin degradation on reductant concentration followed hyperbolic saturation kinetics, and differences between the reductants were manifested in large variations in their half-saturating concentrations (K mR app). Theoretical analyses revealed that K mR app decreases with a decreasing rate of polysaccharide-independent LPMO reoxidation (by either O2 or H2O2). We conclude that the efficiency of LPMO priming depends on the relative contributions of reductant reactivity, on the LPMO's polysaccharide monooxygenase/peroxygenase and reductant oxidase/peroxidase activities, and on reaction conditions, such as O2, H2O2, and polysaccharide concentrations.
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Affiliation(s)
- Silja Kuusk
- Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia
| | - Riin Kont
- Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia
| | - Piret Kuusk
- Institute of Molecular and Physics, University of Tartu, 51010 Tartu, Estonia
| | - Agnes Heering
- Institute of Molecular and Chemistry, University of Tartu, 51010 Tartu, Estonia
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, 1433 Ås, Norway
| | - Bastien Bissaro
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, 1433 Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, 1433 Ås, Norway
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia.
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Kuusk S, Bissaro B, Kuusk P, Forsberg Z, Eijsink VGH, Sørlie M, Väljamäe P. Kinetics of H 2O 2-driven degradation of chitin by a bacterial lytic polysaccharide monooxygenase. J Biol Chem 2018; 293:12284. [PMID: 30076256 DOI: 10.1074/jbc.aac118.004796] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Madhuprakash J, Dalhus B, Rani TS, Podile AR, Eijsink VGH, Sørlie M. Key Residues Affecting Transglycosylation Activity in Family 18 Chitinases: Insights into Donor and Acceptor Subsites. Biochemistry 2018; 57:4325-4337. [DOI: 10.1021/acs.biochem.8b00381] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jogi Madhuprakash
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Bjørn Dalhus
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, P.O.
Box 4950, Nydalen, N-0424 Oslo, Norway
- Department of Microbiology, Clinic for Laboratory Medicine, Oslo University Hospital, Rikshospitalet, P.O. Box 4950, Nydalen, N-0424 Oslo, Norway
| | - T. Swaroopa Rani
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Appa Rao Podile
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Vincent G. H. Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway
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Westereng B, Loose JSM, Vaaje-Kolstad G, Aachmann FL, Sørlie M, Eijsink VGH. Analytical Tools for Characterizing Cellulose-Active Lytic Polysaccharide Monooxygenases (LPMOs). Methods Mol Biol 2018; 1796:219-246. [PMID: 29856057 DOI: 10.1007/978-1-4939-7877-9_16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Lytic polysaccharide monooxygenases are copper-dependent enzymes that perform oxidative cleavage of glycosidic bonds in cellulose and various other polysaccharides. LPMOs acting on cellulose use a reactive oxygen species to abstract a hydrogen from the C1 or C4, followed by hydroxylation of the resulting substrate radical. The resulting hydroxylated species is unstable, resulting in glycoside bond scission and formation of an oxidized new chain end. These oxidized chain ends are spontaneously hydrated at neutral pH, leading to formation of an aldonic acid or a gemdiol, respectively. LPMO activity may be characterized using a variety of analytic tools, the most common of which are high-performance anion exchange chromatography system with pulsed amperometric detection (HPAEC-PAD) and MALDI-TOF mass spectrometry (MALDI-MS). NMR may be used to increase the certainty of product identifications, in particular the site of oxidation. Kinetic studies of LPMOs have several pitfalls and to avoid these, it is important to secure copper saturation, avoid the presence of free transition metals in solution, and control the amount of reductant (i.e., electron supply to the LPMO). Further insight into LPMO properties may be obtained by determining the redox potential and by determining the affinity for copper. In some cases, substrate affinity can be assessed using isothermal titration calorimetry. These methods are described in this chapter.
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Affiliation(s)
- Bjørge Westereng
- Biotechnology and Food Science, Faculty of Chemistry, Norwegian University of Life Sciences, Ås, Norway
| | - Jennifer S M Loose
- Biotechnology and Food Science, Faculty of Chemistry, Norwegian University of Life Sciences, Ås, Norway
| | - Gustav Vaaje-Kolstad
- Biotechnology and Food Science, Faculty of Chemistry, Norwegian University of Life Sciences, Ås, Norway
| | - Finn L Aachmann
- Department of Biotechnology and Food Science, NOBIPOL, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Morten Sørlie
- Biotechnology and Food Science, Faculty of Chemistry, Norwegian University of Life Sciences, Ås, Norway
| | - Vincent G H Eijsink
- Biotechnology and Food Science, Faculty of Chemistry, Norwegian University of Life Sciences, Ås, Norway.
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Kuusk S, Bissaro B, Kuusk P, Forsberg Z, Eijsink VGH, Sørlie M, Väljamäe P. Kinetics of H 2O 2-driven degradation of chitin by a bacterial lytic polysaccharide monooxygenase. J Biol Chem 2017; 293:523-531. [PMID: 29138240 DOI: 10.1074/jbc.m117.817593] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/31/2017] [Indexed: 11/06/2022] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) catalyze the oxidative cleavage of glycosidic bonds in recalcitrant polysaccharides, such as cellulose and chitin, and are of interest in biotechnological utilization of these abundant biomaterials. It has recently been shown that LPMOs can use H2O2, instead of O2, as a cosubstrate. This peroxygenase-like reaction by a monocopper enzyme is unprecedented in nature and opens new avenues in chemistry and enzymology. Here, we provide the first detailed kinetic characterization of chitin degradation by the bacterial LPMO chitin-binding protein CBP21 using H2O2 as cosubstrate. The use of 14C-labeled chitin provided convenient and sensitive detection of the released soluble products, which enabled detailed kinetic measurements. The kcat for chitin oxidation found here (5.6 s-1) is more than an order of magnitude higher than previously reported (apparent) rate constants for reactions containing O2 but no added H2O2 The kcat/Km for H2O2-driven degradation of chitin was on the order of 106 m-1 s-1, indicating that LPMOs have catalytic efficiencies similar to those of peroxygenases. Of note, H2O2 also inactivated CBP21, but the second-order rate constant for inactivation was about 3 orders of magnitude lower than that for catalysis. In light of the observed CBP21 inactivation at higher H2O2 levels, we conclude that controlled generation of H2O2in situ seems most optimal for fueling LPMO-catalyzed oxidation of polysaccharides.
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Affiliation(s)
- Silja Kuusk
- From the Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia
| | - Bastien Bissaro
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1433 Ås, Norway, and
| | - Piret Kuusk
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia
| | - Zarah Forsberg
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1433 Ås, Norway, and
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1433 Ås, Norway, and
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1433 Ås, Norway, and
| | - Priit Väljamäe
- From the Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia,
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32
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Ohnuma T, Taira T, Umemoto N, Kitaoku Y, Sørlie M, Numata T, Fukamizo T. Crystal structure and thermodynamic dissection of chitin oligosaccharide binding to the LysM module of chitinase-A from Pteris ryukyuensis. Biochem Biophys Res Commun 2017; 494:736-741. [PMID: 28867184 DOI: 10.1016/j.bbrc.2017.08.143] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 08/24/2017] [Indexed: 01/08/2023]
Abstract
We determined the crystal structure of a LysM module from Pteris ryukyuensis chitinase-A (PrLysM2) at a resolution of 1.8 Å. Structural and binding analysis of PrLysM2 indicated that this module recognizes chitin oligosaccharides in a shallow groove comprised of five sugar-binding subsites on one side of the molecule. The free energy changes (ΔGr°) for binding of (GlcNAc)6, (GlcNAc)5, and (GlcNAc)4 to PrLysM2 were determined to be -5.4, -5,4 and -4.6 kcal mol-1, respectively, by ITC. Thermodynamic dissection of the binding energetics of (GlcNAc)6 revealed that the driving force is the enthalpy change (ΔHr° = -11.7 ± 0.2 kcal/mol) and the solvation entropy change (-TΔSsolv° = -5.9 ± 0.6 kcal/mol). This is the first description of thermodynamic signatures of a chitin oligosaccharide binding to a LysM module.
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Affiliation(s)
- Takayuki Ohnuma
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara 631-8505, Japan.
| | - Toki Taira
- Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyus, Okinawa, Japan
| | - Naoyuki Umemoto
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara 631-8505, Japan
| | - Yoshihito Kitaoku
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara 631-8505, Japan
| | - Morten Sørlie
- Department of Chemistry, Biotechnology, and Food Science, The Norwegian University of Life Sciences, 1432 Ås, Norway
| | - Tomoyuki Numata
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566, Japan
| | - Tamo Fukamizo
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara 631-8505, Japan
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Hamre AG, Frøberg EE, Eijsink VGH, Sørlie M. Thermodynamics of tunnel formation upon substrate binding in a processive glycoside hydrolase. Arch Biochem Biophys 2017; 620:35-42. [PMID: 28359644 DOI: 10.1016/j.abb.2017.03.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/20/2017] [Accepted: 03/23/2017] [Indexed: 11/18/2022]
Abstract
Glycoside hydrolases (GHs) catalyze the hydrolysis of glycosidic bonds and are key enzymes in carbohydrate metabolism. Efficient degradation of recalcitrant polysaccharides such as chitin and cellulose is accomplished due to synergistic enzyme cocktails consisting of accessory enzymes and mixtures of GHs with different modes of action and active site topologies. The substrate binding sites of chitinases and cellulases often have surface exposed aromatic amino acids and a tunnel or cleft topology. The active site of the exo-processive chitinase B (ChiB) from Serratia marcescens is partially closed, creating a tunnel-like catalytic cleft. To gain insight in the fundamental principles of substrate binding in this enzyme, we have studied the contribution of five key residues involved in substrate binding and tunnel formation to the thermodynamics of substrate binding. Mutation of Trp97, Phe190, Trp220 and Glu221, which are all part of the tunnel walls, resulted in significant less favorable conformational entropy change (ΔS°conf) upon binding (-TΔΔS°conf = ∼5 kcal/mol). This suggest that these residues are important for the structural rigidity and pre-shaping of the tunnel prior to binding. Mutation of Asp316, which, by forming a hydrogen bond to Trp97 is crucial in the active-site tunnel roof, resulted in a more favorable ΔS°conf relative to the wild type (-TΔΔS°conf = -2.2 kcal/mol). This shows that closing the tunnel-roof comes with an entropy cost, as previously suggested based on the crystal structures of GHs with tunnel topologies in complex with their substrates.
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Affiliation(s)
- Anne Grethe Hamre
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Emil Ebbestad Frøberg
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway.
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Abstract
Human chitotriosidase (HCHT) is involved in immune response to chitin-containing pathogens in humans. The enzyme is able to degrade chitooligosaccharides as well as crystalline chitin. The catalytic domain of HCHT is connected to the carbohydrate binding module (CBM) through a flexible hinge region. In humans, two active isoforms of HCHT are found-the full length enzyme and its truncated version lacking CBM and the hinge region. The active site architecture of HCHT is reminiscent to that of the reducing-end exo-acting processive chitinase ChiA from bacterium Serratia marcescens (SmChiA). However, the presence of flexible hinge region and occurrence of two active isoforms are reminiscent to that of non-processive endo-chitinase from S. marcescens, SmChiC. Although the studies on soluble chitin derivatives suggest the endo-character of HCHT, the mode of action of the enzyme on crystalline chitin is not known. Here, we made a thorough characterization of HCHT in terms of the mode of action, processivity, binding, and rate constants for the catalysis and dissociation using α-chitin as substrate. HCHT efficiently released the end-label from reducing-end labelled chitin and had also high probability (95%) of endo-mode initiation of processive run. These results qualify HCHT as an endo-processive enzyme. Processivity and the rate constant of dissociation of HCHT were found to be in-between those, characteristic to processive exo-enzymes, like SmChiA and randomly acting non-processive endo-enzymes, like SmChiC. Apart from increasing the affinity for chitin, CBM had no major effect on kinetic properties of HCHT.
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Affiliation(s)
- Silja Kuusk
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- * E-mail:
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
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35
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Jana S, Hamre AG, Wildberger P, Holen MM, Eijsink VGH, Beckham GT, Sørlie M, Payne CM. Aromatic-Mediated Carbohydrate Recognition in Processive Serratia marcescens Chitinases. J Phys Chem B 2016; 120:1236-49. [PMID: 26824449 DOI: 10.1021/acs.jpcb.5b12610] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Microorganisms use a host of enzymes, including processive glycoside hydrolases, to deconstruct recalcitrant polysaccharides to sugars. Processive glycoside hydrolases closely associate with polymer chains and repeatedly cleave glycosidic linkages without dissociating from the crystalline surface after each hydrolytic step; they are typically the most abundant enzymes in both natural secretomes and industrial cocktails by virtue of their significant hydrolytic potential. The ubiquity of aromatic residues lining the enzyme catalytic tunnels and clefts is a notable feature of processive glycoside hydrolases. We hypothesized that these aromatic residues have uniquely defined roles, such as substrate chain acquisition and binding in the catalytic tunnel, that are defined by their local environment and position relative to the substrate and the catalytic center. Here, we investigated this hypothesis with variants of Serratia marcescens family 18 processive chitinases ChiA and ChiB. We applied molecular simulation and free energy calculations to assess active site dynamics and ligand binding free energies. Isothermal titration calorimetry provided further insight into enthalpic and entropic contributions to ligand binding free energy. Thus, the roles of six aromatic residues, Trp-167, Trp-275, and Phe-396 in ChiA, and Trp-97, Trp-220, and Phe-190 in ChiB, have been examined. We observed that point mutation of the tryptophan residues to alanine results in unfavorable changes in the free energy of binding relative to wild-type. The most drastic effects were observed for residues positioned at the "entrances" of the deep substrate-binding clefts and known to be important for processivity. Interestingly, phenylalanine mutations in ChiA and ChiB had little to no effect on chito-oligomer binding, in accordance with the limited effects of their removal on chitinase functionality.
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Affiliation(s)
- Suvamay Jana
- Department of Chemical and Materials Engineering, University of Kentucky , Lexington, Kentucky 40506-0046, United States
| | - Anne Grethe Hamre
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences , Ås 1430, Norway
| | - Patricia Wildberger
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences , Ås 1430, Norway
| | - Matilde Mengkrog Holen
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences , Ås 1430, Norway
| | - Vincent G H Eijsink
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences , Ås 1430, Norway
| | - Gregg T Beckham
- National Bioenergy Center, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Morten Sørlie
- Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences , Ås 1430, Norway
| | - Christina M Payne
- Department of Chemical and Materials Engineering, University of Kentucky , Lexington, Kentucky 40506-0046, United States
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36
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Eide KB, Stockinger LW, Lewin AS, Tøndervik A, Eijsink VG, Sørlie M. The role of active site aromatic residues in substrate degradation by the human chitotriosidase. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2016; 1864:242-7. [DOI: 10.1016/j.bbapap.2015.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 11/16/2015] [Accepted: 11/23/2015] [Indexed: 11/15/2022]
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37
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Hamre AG, Jana S, Reppert NK, Payne CM, Sørlie M. Processivity, Substrate Positioning, and Binding: The Role of Polar Residues in a Family 18 Glycoside Hydrolase. Biochemistry 2015; 54:7292-306. [PMID: 26503416 DOI: 10.1021/acs.biochem.5b00830] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The enzymatic degradation of recalcitrant polysaccharides such as cellulose (β-1,4-linked glucose) and chitin (β-1,4-linked N-acetylglucosamine) by glycoside hydrolases (GHs) is of significant biological and economical importance. In nature, depolymerization is primarily accomplished by processive GHs, which remain attached to the substrate between subsequent hydrolytic reactions. Recent computational efforts have suggested that the processive ability of a GH is directly linked to the ligand binding free energy. The contribution of individual aromatic residues in the active site of these enzymes has been extensively studied. In this study, we offer the first experimental evidence confirming correlation of binding free energy and degree of processivity and evidence that polar residues are essential for maintaining processive ability. Exchanging Thr(276) with Ala in substrate binding subsite -2 in the processive ChiA of Serratia marcescens results in a decrease in both the enthalpy (2.6 and 3.8 kcal/mol) and free energy (0.5 and 2.2 kcal/mol) for the binding to the substrate (GlcNAc)6 and the inhibitor allosamidin, respectively, compared to that of the wild type. Moreover, the initial apparent processivity as measured by [(GlcNAc)2]/[GlcNAc] ratios (17.1 ± 0.4) and chitin degradation efficiency (20%) are greatly reduced for ChiA-T276A versus those of the wild type (30.1 ± 1.5 and 75%, respectively). Mutation of Arg(172) to Ala reduces the level of recognition and positioning of the substrate into the active site. Molecular dynamics simulations indicate ChiA-R172A behaves like the wild type, but the dynamics of ChiA-T276A are greatly influenced by mutation, which is reflective of their influence on processivity.
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Affiliation(s)
- Anne Grethe Hamre
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås, Norway
| | - Suvamay Jana
- Department of Chemical and Materials Engineering, University of Kentucky , Lexington, Kentucky 40506, United States
| | - Nicole K Reppert
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås, Norway
| | - Christina M Payne
- Department of Chemical and Materials Engineering, University of Kentucky , Lexington, Kentucky 40506, United States
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås, Norway
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Kurašin M, Kuusk S, Kuusk P, Sørlie M, Väljamäe P. Slow Off-rates and Strong Product Binding Are Required for Processivity and Efficient Degradation of Recalcitrant Chitin by Family 18 Chitinases. J Biol Chem 2015; 290:29074-85. [PMID: 26468285 DOI: 10.1074/jbc.m115.684977] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Indexed: 12/18/2022] Open
Abstract
Processive glycoside hydrolases are the key components of enzymatic machineries that decompose recalcitrant polysaccharides, such as chitin and cellulose. The intrinsic processivity (P(Intr)) of cellulases has been shown to be governed by the rate constant of dissociation from polymer chain (koff). However, the reported koff values of cellulases are strongly dependent on the method used for their measurement. Here, we developed a new method for determining koff, based on measuring the exchange rate of the enzyme between a non-labeled and a (14)C-labeled polymeric substrate. The method was applied to the study of the processive chitinase ChiA from Serratia marcescens. In parallel, ChiA variants with weaker binding of the N-acetylglucosamine unit either in substrate-binding site -3 (ChiA-W167A) or the product-binding site +1 (ChiA-W275A) were studied. Both ChiA variants showed increased off-rates and lower apparent processivity on α-chitin. The rate of the production of insoluble reducing groups on the reduced α-chitin was an order of magnitude higher than koff, suggesting that the enzyme can initiate several processive runs without leaving the substrate. On crystalline chitin, the general activity of the wild type enzyme was higher, and the difference was magnifying with hydrolysis time. On amorphous chitin, the variants clearly outperformed the wild type. A model is proposed whereby strong interactions with polymer in the substrate-binding sites (low off-rates) and strong binding of the product in the product-binding sites (high pushing potential) are required for the removal of obstacles, like disintegration of chitin microfibrils.
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Affiliation(s)
| | - Silja Kuusk
- From the Institutes of Molecular and Cell Biology and
| | - Piret Kuusk
- Physics, University of Tartu, 51010 Tartu, Estonia and
| | - Morten Sørlie
- the Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås 1432, Norway
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39
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Stockinger LW, Eide KB, Dybvik AI, Sletta H, Vårum KM, Eijsink VG, Tøndervik A, Sørlie M. The effect of the carbohydrate binding module on substrate degradation by the human chitotriosidase. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2015; 1854:1494-501. [DOI: 10.1016/j.bbapap.2015.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 05/29/2015] [Accepted: 06/23/2015] [Indexed: 11/25/2022]
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40
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Hamre AG, Jana S, Holen MM, Mathiesen G, Väljamäe P, Payne CM, Sørlie M. Thermodynamic Relationships with Processivity in Serratia marcescens Family 18 Chitinases. J Phys Chem B 2015; 119:9601-13. [PMID: 26154587 DOI: 10.1021/acs.jpcb.5b03817] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The enzymatic degradation of recalcitrant polysaccharides is accomplished by synergistic enzyme cocktails of glycoside hydrolases (GHs) and accessory enzymes. Many GHs are processive which means that they remain attached to the substrate in between subsequent hydrolytic reactions. Chitinases are GHs that catalyze the hydrolysis of chitin (β-1,4-linked N-acetylglucosamine). Previously, a relationship between active site topology and processivity has been suggested while recent computational efforts have suggested a link between the degree of processivity and ligand binding free energy. We have investigated these relationships by employing computational (molecular dynamics (MD)) and experimental (isothermal titration calorimetry (ITC)) approaches to gain insight into the thermodynamics of substrate binding to Serratia marcescens chitinases ChiA, ChiB, and ChiC. We show that increased processive ability indeed corresponds to more favorable binding free energy and that this likely is a general feature of GHs. Moreover, ligand binding in ChiB is entropically driven; in ChiC it is enthalpically driven, and the enthalpic and entropic contributions to ligand binding in ChiA are equal. Furthermore, water is shown to be especially important in ChiA-binding. This work provides new insight into oligosaccharide binding, getting us one step closer to understand how GHs efficiently degrade recalcitrant polysaccharides.
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Affiliation(s)
- Anne Grethe Hamre
- †Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. 5003, N-1432 Ås, Norway
| | - Suvamay Jana
- ‡Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Matilde Mengkrog Holen
- †Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. 5003, N-1432 Ås, Norway
| | - Geir Mathiesen
- †Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. 5003, N-1432 Ås, Norway
| | - Priit Väljamäe
- §Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Christina M Payne
- ‡Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Morten Sørlie
- †Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. 5003, N-1432 Ås, Norway
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41
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Borisova AS, Isaksen T, Dimarogona M, Kognole AA, Mathiesen G, Várnai A, Røhr ÅK, Payne CM, Sørlie M, Sandgren M, Eijsink VGH. Structural and Functional Characterization of a Lytic Polysaccharide Monooxygenase with Broad Substrate Specificity. J Biol Chem 2015; 290:22955-69. [PMID: 26178376 DOI: 10.1074/jbc.m115.660183] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Indexed: 01/02/2023] Open
Abstract
The recently discovered lytic polysaccharide monooxygenases (LPMOs) carry out oxidative cleavage of polysaccharides and are of major importance for efficient processing of biomass. NcLPMO9C from Neurospora crassa acts both on cellulose and on non-cellulose β-glucans, including cellodextrins and xyloglucan. The crystal structure of the catalytic domain of NcLPMO9C revealed an extended, highly polar substrate-binding surface well suited to interact with a variety of sugar substrates. The ability of NcLPMO9C to act on soluble substrates was exploited to study enzyme-substrate interactions. EPR studies demonstrated that the Cu(2+) center environment is altered upon substrate binding, whereas isothermal titration calorimetry studies revealed binding affinities in the low micromolar range for polymeric substrates that are due in part to the presence of a carbohydrate-binding module (CBM1). Importantly, the novel structure of NcLPMO9C enabled a comparative study, revealing that the oxidative regioselectivity of LPMO9s (C1, C4, or both) correlates with distinct structural features of the copper coordination sphere. In strictly C1-oxidizing LPMO9s, access to the solvent-facing axial coordination position is restricted by a conserved tyrosine residue, whereas access to this same position seems unrestricted in C4-oxidizing LPMO9s. LPMO9s known to produce a mixture of C1- and C4-oxidized products show an intermediate situation.
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Affiliation(s)
- Anna S Borisova
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Trine Isaksen
- the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Maria Dimarogona
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Abhishek A Kognole
- the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506
| | - Geir Mathiesen
- the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Anikó Várnai
- the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Åsmund K Røhr
- the Department of Biosciences, University of Oslo, N-0316 Oslo, Norway, and
| | - Christina M Payne
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden, the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506
| | - Morten Sørlie
- the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Mats Sandgren
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden,
| | - Vincent G H Eijsink
- the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway,
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42
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Kuusk S, Sørlie M, Väljamäe P. The predominant molecular state of bound enzyme determines the strength and type of product inhibition in the hydrolysis of recalcitrant polysaccharides by processive enzymes. J Biol Chem 2015; 290:11678-91. [PMID: 25767120 DOI: 10.1074/jbc.m114.635631] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Indexed: 11/06/2022] Open
Abstract
Processive enzymes are major components of the efficient enzyme systems that are responsible for the degradation of the recalcitrant polysaccharides cellulose and chitin. Despite intensive research, there is no consensus on which step is rate-limiting for these enzymes. Here, we performed a comparative study of two well characterized enzymes, the cellobiohydrolase Cel7A from Hypocrea jecorina and the chitinase ChiA from Serratia marcescens. Both enzymes were inhibited by their disaccharide product, namely chitobiose for ChiA and cellobiose for Cel7A. The products behaved as noncompetitive inhibitors according to studies using the (14)C-labeled crystalline polymeric substrates (14)C chitin nanowhiskers and (14)C-labeled bacterial microcrystalline cellulose for ChiA and Cel7A, respectively. The resulting observed Ki (obs) values were 0.45 ± 0.08 mm for ChiA and 0.17 ± 0.02 mm for Cel7A. However, in contrast to ChiA, the Ki (obs) of Cel7A was an order of magnitude higher than the true Ki value governed by the thermodynamic stability of the enzyme-inhibitor complex. Theoretical analysis of product inhibition suggested that the inhibition strength and pattern can be accounted for by assuming different rate-limiting steps for ChiA and Cel7A. Measuring the population of enzymes whose active site was occupied by a polymer chain revealed that Cel7A was bound predominantly via its active site. Conversely, the active-site-mediated binding of ChiA was slow, and most ChiA exhibited a free active site, even when the substrate concentration was saturating for the activity. Collectively, our data suggest that complexation with the polymer chain is rate-limiting for ChiA, whereas Cel7A is limited by dissociation.
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Affiliation(s)
- Silja Kuusk
- From the Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia and
| | - Morten Sørlie
- the Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Priit Väljamäe
- From the Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia and
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43
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Kalayou S, Ndossi D, Frizzell C, Groseth PK, Connolly L, Sørlie M, Verhaegen S, Ropstad E. An investigation of the endocrine disrupting potential of enniatin B using in vitro bioassays. Toxicol Lett 2015; 233:84-94. [DOI: 10.1016/j.toxlet.2015.01.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 01/22/2015] [Accepted: 01/23/2015] [Indexed: 12/01/2022]
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Frizzell C, Uhlig S, Miles CO, Verhaegen S, Elliott CT, Eriksen GS, Sørlie M, Ropstad E, Connolly L. Biotransformation of zearalenone and zearalenols to their major glucuronide metabolites reduces estrogenic activity. Toxicol In Vitro 2015; 29:575-81. [PMID: 25645597 DOI: 10.1016/j.tiv.2015.01.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 01/09/2015] [Accepted: 01/11/2015] [Indexed: 11/17/2022]
Abstract
Zearalenone (ZEN) is a mycotoxin produced by Fusarium fungi. Once ingested, ZEN may be absorbed and metabolised to α- and β-zearalenol (α-ZOL, β-ZOL), and to a lesser extent α- and β-zearalanol (α-ZAL, β-ZAL). Further biotransformation to glucuronide conjugates also occurs to facilitate the elimination of these toxins from the body. Unlike ZEN and its metabolites, information regarding the estrogenic activity of these glucuronide conjugates in various tissues is lacking. ZEN-14-O-glucuronide, α-ZOL-14-O-glucuronide, α-ZOL-7-O-glucuronide, β-ZOL-14-O-glucuronide and β-ZOL-16-O-glucuronide, previously obtained as the major products from preparative enzymatic synthesis, were investigated for their potential to cause endocrine disruption through interference with estrogen receptor transcriptional activity. All five glucuronide conjugates showed a very weak agonist response in an estrogen responsive reporter gene assay (RGA), with activity ranging from 0.0001% to 0.01% of that of 17β-estradiol, and also less than that of ZEN, α-ZOL and β-ZOL which have previously shown estrogenic potencies of the order 17β-estradiol>α-ZOL>ZEN>β-ZOL. Confirmatory mass spectrometry revealed that any activity observed was likely a result of minor deconjugation of the glucuronide moiety. This study confirms that formation of ZEN and ZOL glucuronides is a detoxification reaction with regard to estrogenicity, serving as a potential host defence mechanism against ZEN-induced estrogenic activity.
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Affiliation(s)
- Caroline Frizzell
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Northern Ireland, United Kingdom.
| | - Silvio Uhlig
- Section for Chemistry and Toxicology, Norwegian Veterinary Institute, Oslo, Norway.
| | - Christopher O Miles
- Section for Chemistry and Toxicology, Norwegian Veterinary Institute, Oslo, Norway.
| | | | - Christopher T Elliott
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Northern Ireland, United Kingdom.
| | - Gunnar S Eriksen
- Section for Chemistry and Toxicology, Norwegian Veterinary Institute, Oslo, Norway.
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
| | - Erik Ropstad
- Norwegian School of Veterinary Science, Oslo, Norway.
| | - Lisa Connolly
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Northern Ireland, United Kingdom.
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45
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Kalayou S, Hamre AG, Ndossi D, Connolly L, Sørlie M, Ropstad E, Verhaegen S. Using SILAC proteomics to investigate the effect of the mycotoxin, alternariol, in the human H295R steroidogenesis model. Cell Biol Toxicol 2014; 30:361-76. [PMID: 25416481 DOI: 10.1007/s10565-014-9290-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 11/07/2014] [Indexed: 01/07/2023]
Abstract
The mycotoxin alternariol (AOH) is an important contaminant of fruits and cereal products. The current study sought to address the effect of a non-toxic AOH concentration on the proteome of the steroidogenic H295R cell model. Quantitative proteomics based on stable isotope labeling by amino acids in cell culture (SILAC) coupled to 1D-SDS-PAGE-LC-MS/MS was applied to subcellular-enriched protein samples. Gene ontology (GO) and ingenuity pathway analysis (IPA) were further carried out for functional annotation and identification of protein interaction networks. Furthermore, the effect of AOH on apoptosis and cell cycle distribution was also determined by the use of flow cytometry analysis. This work identified 22 proteins that were regulated significantly. The regulated proteins are those involved in early stages of steroid biosynthesis (SOAT1, NPC1, and ACBD5) and C21-steroid hormone metabolism (CYP21A2 and HSD3B1). In addition, several proteins known to play a role in cellular assembly, organization, protein synthesis, and cell cycle were regulated. These findings provide a new framework for studying the mechanisms by which AOH modulates steroidogenesis in H295R cell model.
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46
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Forsberg Z, Røhr AK, Mekasha S, Andersson KK, Eijsink VGH, Vaaje-Kolstad G, Sørlie M. Comparative study of two chitin-active and two cellulose-active AA10-type lytic polysaccharide monooxygenases. Biochemistry 2014; 53:1647-56. [PMID: 24559135 DOI: 10.1021/bi5000433] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Lytic polysaccharide monooxygenases (LPMOs), found in family 9 (previously GH61), family 10 (previously CBM33), and the newly discovered family 11 of auxiliary activities (AA) in the carbohydrate-active enzyme classification system, are copper-dependent enzymes that oxidize sp(3)-carbons in recalcitrant polysaccharides such as chitin and cellulose in the presence of an external electron donor. In this study, we describe the activity of two AA10-type LPMOs whose activities have not been described before and we compare in total four different AA10-type LPMOs with the aim of finding possible correlations between their substrate specificities, sequences, and EPR signals. EPR spectra indicate that the electronic environment of the copper varies within the AA10 family even though amino acids directly interacting with the copper atom are identical in all four enzymes. This variation seems to be correlated to substrate specificity and is likely caused by sequence variation in areas that affect substrate binding geometry and/or by variation in a cluster of conserved aromatic residues likely involved in electron transfer. Interestingly, EPR signals for cellulose-active AA10 enzymes were similar to those previously observed for cellulose-active AA9 enzymes. Mutation of the conserved phenylalanine positioned in close proximity to the copper center in AA10-type LPMOs to Tyr (the corresponding residue in most AA9-type LPMOs) or Ala, led to complete or partial inactivation, respectively, while in both cases the ability to bind copper was maintained. Moreover, substrate binding affinity and degradation ability seemed hardly correlated, further emphasizing the crucial role of the active site configuration in determining LPMO functionality.
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Affiliation(s)
- Zarah Forsberg
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås, Norway
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47
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Eide KB, Lindbom AR, Eijsink VG, Norberg AL, Sørlie M. Analysis of productive binding modes in the human chitotriosidase. FEBS Lett 2013; 587:3508-13. [DOI: 10.1016/j.febslet.2013.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 09/02/2013] [Accepted: 09/03/2013] [Indexed: 10/26/2022]
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48
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Frizzell C, Ndossi D, Kalayou S, Eriksen GS, Verhaegen S, Sørlie M, Elliott CT, Ropstad E, Connolly L. An in vitro investigation of endocrine disrupting effects of the mycotoxin alternariol. Toxicol Appl Pharmacol 2013; 271:64-71. [PMID: 23665424 DOI: 10.1016/j.taap.2013.05.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 04/26/2013] [Accepted: 05/02/2013] [Indexed: 11/18/2022]
Abstract
Alternariol (AOH) is a mycotoxin commonly produced by Alternaria alternata on a wide range of foods. Few studies to date have been performed to evaluate the effects of AOH on endocrine activity. The present study makes use of in vitro mammalian cellular based assays and gene expression to investigate the ability of AOH to act as an endocrine disruptor by various modes of action. Reporter gene assays (RGAs), incorporating natural steroid hormone receptors for oestrogens, androgens, progestagens and glucocorticoids were used to identify endocrine disruption at the level of nuclear receptor transcriptional activity, and the H295R steroidogenesis assay was used to assess endocrine disruption at the level of gene expression and steroid hormone production. AOH exhibited a weak oestrogenic response when tested in the oestrogen responsive RGA and binding of progesterone to the progestagen receptor was shown to be synergistically increased in the presence of AOH. H295R cells when exposed to 0.1-1000ng/ml AOH, did not cause a significant change in testosterone and cortisol hormones but exposure to 1000ng/ml (3.87μM) AOH resulted in a significant increase in estradiol and progesterone production. In the gene expression study following exposure to 1000ng/ml (3.87μM) AOH, only one gene NR0B1 was down-regulated, whereas expression of mRNA for CYP1A1, MC2R, HSD3B2, CYP17, CYP21, CYP11B2 and CYP19 was up-regulated. Expression of the other genes investigated did not change significantly. In conclusion AOH is a weak oestrogenic mycotoxin that also has the ability to interfere with the steroidogenesis pathway.
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MESH Headings
- Androgens/metabolism
- Cell Line, Tumor
- Dose-Response Relationship, Drug
- Down-Regulation/drug effects
- Endocrine Disruptors/administration & dosage
- Endocrine Disruptors/toxicity
- Estrogens/metabolism
- Genes, Reporter
- Glucocorticoids/metabolism
- Humans
- Lactones/administration & dosage
- Lactones/toxicity
- Progestins/metabolism
- RNA, Messenger/metabolism
- Receptors, Androgen/genetics
- Receptors, Androgen/metabolism
- Receptors, Estrogen/genetics
- Receptors, Estrogen/metabolism
- Receptors, Glucocorticoid/genetics
- Receptors, Glucocorticoid/metabolism
- Receptors, Progesterone/genetics
- Receptors, Progesterone/metabolism
- Up-Regulation/drug effects
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Affiliation(s)
- Caroline Frizzell
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Northern Ireland, UK
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49
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Quintero-Villegas MI, Aam BB, Rupnow J, Sørlie M, Eijsink VGH, Hutkins RW. Adherence inhibition of enteropathogenic Escherichia coli by chitooligosaccharides with specific degrees of acetylation and polymerization. J Agric Food Chem 2013; 61:2748-2754. [PMID: 23428168 DOI: 10.1021/jf400103g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Some oligosaccharides are known to act as molecular decoys by inhibiting pathogen adherence to epithelial cells. The present study was aimed at analyzing whether chitooligosaccharides (CHOS), that is, oligomers of D-glucosamine and N-acetyl-D-glucosamine, have such antiadherence activity. CHOS of varied degree of polymerization (DP) and fraction of acetylation (F(A)) were produced. Adherence of enteropathogenic Escherichia coli (EPEC) to the surface of a human HEp-2 cell line was determined in the absence or presence of the various CHOS fractions. Adherence was assessed by microscopic counting and image analysis of bacterial clusters and cells. The results showed that all CHOS fractions inhibited adherence of EPEC to HEp-2 cells. Hydrolysates with lower F(A) were more effective at reducing adherence. This effect is greater than that obtained with other oligosaccharides, such as galactooligosaccharides, applied at the same concentrations.
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Affiliation(s)
- Maria I Quintero-Villegas
- Department of Food Science and Technology, University of Nebraska , Lincoln, Nebraska 68583-0919, United States
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50
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Vaaje-Kolstad G, Horn SJ, Sørlie M, Eijsink VGH. The chitinolytic machinery ofSerratia marcescens- a model system for enzymatic degradation of recalcitrant polysaccharides. FEBS J 2013; 280:3028-49. [DOI: 10.1111/febs.12181] [Citation(s) in RCA: 210] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 01/30/2013] [Accepted: 02/05/2013] [Indexed: 01/13/2023]
Affiliation(s)
- Gustav Vaaje-Kolstad
- Department of Chemistry; Biotechnology and Food Science; Norwegian University of Life Sciences; Ås; Norway
| | - Svein J. Horn
- Department of Chemistry; Biotechnology and Food Science; Norwegian University of Life Sciences; Ås; Norway
| | - Morten Sørlie
- Department of Chemistry; Biotechnology and Food Science; Norwegian University of Life Sciences; Ås; Norway
| | - Vincent G. H. Eijsink
- Department of Chemistry; Biotechnology and Food Science; Norwegian University of Life Sciences; Ås; Norway
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