1
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Okmane L, Fitkin L, Sandgren M, Ståhlberg J. The first crystal structure of a family 45 glycoside hydrolase from a brown-rot fungus, Gloeophyllum trabeum GtCel45A. FEBS Open Bio 2024; 14:505-514. [PMID: 38311343 PMCID: PMC10909974 DOI: 10.1002/2211-5463.13774] [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: 08/31/2023] [Revised: 01/12/2024] [Accepted: 01/22/2024] [Indexed: 02/09/2024] Open
Abstract
Here we describe the first crystal structure of a beta-1,4-endoglucanase from a brown-rot fungus, Gloeophyllum trabeum GtCel45A, which belongs to subfamily C of glycoside hydrolase family 45 (GH45). GtCel45A is ~ 18 kDa in size and the crystal structure contains 179 amino acids. The structure is refined at 1.30 Å resolution and Rfree 0.18. The enzyme consists of a single catalytic module folded into a six-stranded double-psi beta-barrel domain surrounded by long loops. GtCel45A is very similar in sequence (82% identity) and structure to PcCel45A from the white-rot fungus Phanerochaete chrysosporium. Surprisingly though, initial hydrolysis of barley beta-glucan was almost twice as fast in GtCel45A as compared to PcCel45A.
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Affiliation(s)
- Laura Okmane
- Department of Molecular SciencesSwedish University of Agricultural SciencesUppsalaSweden
| | - Louise Fitkin
- Department of Molecular SciencesSwedish University of Agricultural SciencesUppsalaSweden
| | - Mats Sandgren
- Department of Molecular SciencesSwedish University of Agricultural SciencesUppsalaSweden
| | - Jerry Ståhlberg
- Department of Molecular SciencesSwedish University of Agricultural SciencesUppsalaSweden
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2
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Haataja T, Hansson H, Moriya S, Sandgren M, Ståhlberg J. The crystal structure of RsSymEG1 reveals a unique form of smaller GH7 endoglucanases alongside GH7 cellobiohydrolases in protist symbionts of termites. FEBS J 2024; 291:1168-1185. [PMID: 38073120 DOI: 10.1111/febs.17029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/31/2023] [Accepted: 12/08/2023] [Indexed: 12/21/2023]
Abstract
Glycoside hydrolase family 7 (GH7) cellulases are key enzymes responsible for carbon cycling on earth through their role in cellulose degradation and constitute highly important industrial enzymes as well. Although these enzymes are found in a wide variety of evolutionarily distant organisms across eukaryotes, they exhibit remarkably conserved features within two groups: exo-acting cellobiohydrolases and endoglucanases. However, recently reports have emerged of a separate clade of GH7 endoglucanases from protist symbionts of termites that are 60-80 amino acids shorter. In this work, we describe the first crystal structure of a short GH7 endoglucanase, RsSymEG1, from a symbiont of the lower termite Reticulitermes speratus. A more open flat surface and shorter loops around the non-reducing end of the cellulose-binding cleft indicate enhanced access to cellulose chains on the surface of cellulose microfibrils. Additionally, when comparing activities on polysaccharides to a typical fungal GH7 endoglucanase (Trichoderma longibrachiatum Cel7B), RsSymEG1 showed significantly faster initial hydrolytic activity. We also examine the prevalence and diversity of GH7 enzymes that the symbionts provide to the termite host, compare overall structures and substrate binding between cellobiohydrolase and long and short endoglucanase, and highlight the presence of similar short GH7s in other organisms.
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Affiliation(s)
- Topi Haataja
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Henrik Hansson
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
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3
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Zou Y, Sabljić I, Horbach N, Dauphinee AN, Åsman A, Sancho Temino L, Minina EA, Drag M, Stael S, Poreba M, Ståhlberg J, Bozhkov PV. Thermoprotection by a cell membrane-localized metacaspase in a green alga. Plant Cell 2024; 36:665-687. [PMID: 37971931 PMCID: PMC10896300 DOI: 10.1093/plcell/koad289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/10/2023] [Accepted: 11/12/2023] [Indexed: 11/19/2023]
Abstract
Caspases are restricted to animals, while other organisms, including plants, possess metacaspases (MCAs), a more ancient and broader class of structurally related yet biochemically distinct proteases. Our current understanding of plant MCAs is derived from studies in streptophytes, and mostly in Arabidopsis (Arabidopsis thaliana) with 9 MCAs with partially redundant activities. In contrast to streptophytes, most chlorophytes contain only 1 or 2 uncharacterized MCAs, providing an excellent platform for MCA research. Here we investigated CrMCA-II, the single type-II MCA from the model chlorophyte Chlamydomonas (Chlamydomonas reinhardtii). Surprisingly, unlike other studied MCAs and similar to caspases, CrMCA-II dimerizes both in vitro and in vivo. Furthermore, activation of CrMCA-II in vivo correlated with its dimerization. Most of CrMCA-II in the cell was present as a proenzyme (zymogen) attached to the plasma membrane (PM). Deletion of CrMCA-II by genome editing compromised thermotolerance, leading to increased cell death under heat stress. Adding back either wild-type or catalytically dead CrMCA-II restored thermoprotection, suggesting that its proteolytic activity is dispensable for this effect. Finally, we connected the non-proteolytic role of CrMCA-II in thermotolerance to the ability to modulate PM fluidity. Our study reveals an ancient, MCA-dependent thermotolerance mechanism retained by Chlamydomonas and probably lost during the evolution of multicellularity.
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Affiliation(s)
- Yong Zou
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Igor Sabljić
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Natalia Horbach
- Department of Chemical Biology and Bioimaging, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
| | - Adrian N Dauphinee
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Anna Åsman
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Lucia Sancho Temino
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Elena A Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Marcin Drag
- Department of Chemical Biology and Bioimaging, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
| | - Simon Stael
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Marcin Poreba
- Department of Chemical Biology and Bioimaging, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
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4
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Stael S, Sabljić I, Audenaert D, Andersson T, Tsiatsiani L, Kumpf RP, Vidal-Albalat A, Lindgren C, Vercammen D, Jacques S, Nguyen L, Njo M, Fernández-Fernández ÁD, Beunens T, Timmerman E, Gevaert K, Van Montagu M, Ståhlberg J, Bozhkov PV, Linusson A, Beeckman T, Van Breusegem F. Structure-function study of a Ca 2+-independent metacaspase involved in lateral root emergence. Proc Natl Acad Sci U S A 2023; 120:e2303480120. [PMID: 37216519 PMCID: PMC10235996 DOI: 10.1073/pnas.2303480120] [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: 03/01/2023] [Accepted: 04/24/2023] [Indexed: 05/24/2023] Open
Abstract
Metacaspases are part of an evolutionarily broad family of multifunctional cysteine proteases, involved in disease and normal development. As the structure-function relationship of metacaspases remains poorly understood, we solved the X-ray crystal structure of an Arabidopsis thaliana type II metacaspase (AtMCA-IIf) belonging to a particular subgroup not requiring calcium ions for activation. To study metacaspase activity in plants, we developed an in vitro chemical screen to identify small molecule metacaspase inhibitors and found several hits with a minimal thioxodihydropyrimidine-dione structure, of which some are specific AtMCA-IIf inhibitors. We provide mechanistic insight into the basis of inhibition by the TDP-containing compounds through molecular docking onto the AtMCA-IIf crystal structure. Finally, a TDP-containing compound (TDP6) effectively hampered lateral root emergence in vivo, probably through inhibition of metacaspases specifically expressed in the endodermal cells overlying developing lateral root primordia. In the future, the small compound inhibitors and crystal structure of AtMCA-IIf can be used to study metacaspases in other species, such as important human pathogens, including those causing neglected diseases.
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Affiliation(s)
- Simon Stael
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007Uppsala, Sweden
| | - Igor Sabljić
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007Uppsala, Sweden
| | - Dominique Audenaert
- VIB Screening Core, VIB,9052Ghent, Belgium
- Centre for Bioassay Development and Screening, Ghent University,9000Ghent, Belgium
| | | | - Liana Tsiatsiani
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | | | | | | | - Dominique Vercammen
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Silke Jacques
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Long Nguyen
- VIB Screening Core, VIB,9052Ghent, Belgium
- Centre for Bioassay Development and Screening, Ghent University,9000Ghent, Belgium
| | - Maria Njo
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Álvaro D. Fernández-Fernández
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Tine Beunens
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Evy Timmerman
- Department of Biomolecular Medicine, Ghent University,9052Ghent, Belgium
- Center for Medical Biotechnology, VIB, 9052Ghent, Belgium
| | - Kris Gevaert
- Department of Biomolecular Medicine, Ghent University,9052Ghent, Belgium
- Center for Medical Biotechnology, VIB, 9052Ghent, Belgium
| | - Marc Van Montagu
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007Uppsala, Sweden
| | - Peter V. Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007Uppsala, Sweden
| | - Anna Linusson
- Department of Chemistry, Umeå University,90187Umeå, Sweden
| | - Tom Beeckman
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
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5
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Haataja T, Gado JE, Nutt A, Anderson NT, Nilsson M, Momeni MH, Isaksson R, Väljamäe P, Johansson G, Payne CM, Ståhlberg J. Enzyme kinetics by GH7 cellobiohydrolases on chromogenic substrates is dictated by non-productive binding: insights from crystal structures and MD simulation. FEBS J 2023; 290:379-399. [PMID: 35997626 PMCID: PMC10087753 DOI: 10.1111/febs.16602] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [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: 06/09/2022] [Revised: 07/30/2022] [Accepted: 08/17/2022] [Indexed: 02/05/2023]
Abstract
Cellobiohydrolases (CBHs) in the glycoside hydrolase family 7 (GH7) (EC3.2.1.176) are the major cellulose degrading enzymes both in industrial settings and in the context of carbon cycling in nature. Small carbohydrate conjugates such as p-nitrophenyl-β-d-cellobioside (pNPC), p-nitrophenyl-β-d-lactoside (pNPL) and methylumbelliferyl-β-d-cellobioside have commonly been used in colorimetric and fluorometric assays for analysing activity of these enzymes. Despite the similar nature of these compounds the kinetics of their enzymatic hydrolysis vary greatly between the different compounds as well as among different enzymes within the GH7 family. Through enzyme kinetics, crystallographic structure determination, molecular dynamics simulations, and fluorometric binding studies using the closely related compound o-nitrophenyl-β-d-cellobioside (oNPC), in this work we examine the different hydrolysis characteristics of these compounds on two model enzymes of this class, TrCel7A from Trichoderma reesei and PcCel7D from Phanerochaete chrysosporium. Protein crystal structures of the E212Q mutant of TrCel7A with pNPC and pNPL, and the wildtype TrCel7A with oNPC, reveal that non-productive binding at the product site is the dominating binding mode for these compounds. Enzyme kinetics results suggest the strength of non-productive binding is a key determinant for the activity characteristics on these substrates, with PcCel7D consistently showing higher turnover rates (kcat ) than TrCel7A, but higher Michaelis-Menten (KM ) constants as well. Furthermore, oNPC turned out to be useful as an active-site probe for fluorometric determination of the dissociation constant for cellobiose on TrCel7A but could not be utilized for the same purpose on PcCel7D, likely due to strong binding to an unknown site outside the active site.
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Affiliation(s)
- Topi Haataja
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Japheth E Gado
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA.,Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Anu Nutt
- Department of Chemistry, Uppsala University, Sweden.,Institute of Molecular and Cell Biology, University of Tartu, Estonia
| | - Nolan T Anderson
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Mikael Nilsson
- Institute of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Majid Haddad Momeni
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Roland Isaksson
- Institute of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Estonia
| | | | - Christina M Payne
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
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6
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Okmane L, Nestor G, Jakobsson E, Xu B, Igarashi K, Sandgren M, Kleywegt GJ, Ståhlberg J. Glucomannan and beta-glucan degradation by Mytilus edulis Cel45A: Crystal structure and activity comparison with GH45 subfamily A, B and C. Carbohydr Polym 2022; 277:118771. [PMID: 34893216 DOI: 10.1016/j.carbpol.2021.118771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/24/2021] [Accepted: 10/11/2021] [Indexed: 11/26/2022]
Abstract
The enzymatic hydrolysis of barley beta-glucan, konjac glucomannan and carboxymethyl cellulose by a β-1,4-D-endoglucanase MeCel45A from blue mussel, Mytilus edulis, which belongs to subfamily B of glycoside hydrolase family 45 (GH45), was compared with GH45 members of subfamilies A (Humicola insolens HiCel45A), B (Trichoderma reesei TrCel45A) and C (Phanerochaete chrysosporium PcCel45A). Furthermore, the crystal structure of MeCel45A is reported. Initial rates and hydrolysis yields were determined by reducing sugar assays and product formation was characterized using NMR spectroscopy. The subfamily B and C enzymes exhibited mannanase activity, whereas the subfamily A member was uniquely able to produce monomeric glucose. All enzymes were confirmed to be inverting glycoside hydrolases. MeCel45A appears to be cold adapted by evolution, as it maintained 70% activity on cellohexaose at 4 °C relative to 30 °C, compared to 35% for TrCel45A. Both enzymes produced cellobiose and cellotetraose from cellohexaose, but TrCel45A additionally produced cellotriose.
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Affiliation(s)
- Laura Okmane
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Gustav Nestor
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Emma Jakobsson
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Bingze Xu
- Center for Surface Biotechnology, Uppsala University, Uppsala, Sweden
| | - Kiyohiko Igarashi
- Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Gerard J Kleywegt
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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7
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Sabljić I, Zou Y, Klemenčič M, Funk C, Ståhlberg J, Bozhkov P. Expression and Purification of the Type II Metacaspase from a Unicellular Green Alga Chlamydomonas reinhardtii. Methods Mol Biol 2022; 2447:13-20. [PMID: 35583769 DOI: 10.1007/978-1-0716-2079-3_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Type II metacaspases (MCAs) are proteases, belonging to the C14B MEROPS family. Like the MCAs of type I and type III, they preferentially cleave their substrates after the positively charged amino acid residues (Arg or Lys) at the P1 position. Type II MCAs from various higher plants have already been successfully overexpressed in E. coli mostly as His-tagged proteins and were shown to be proteolytically active after the purification. Here we present a protocol for expression and purification of the only type II MCA from the model green alga Chlamydomonas reinhardtii. The two-step purification, which consists of immobilized metal affinity chromatography using cobalt as ion followed by size-exclusion chromatography, can be performed in 1 day and yields 4 mg CrMCA-II protein per liter of overexpression culture.
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Affiliation(s)
- Igor Sabljić
- Uppsala BioCenter, Department of Molecular Science, Swedish University of Agricultural Sciences, Uppsala, Sweden.
| | - Yong Zou
- Uppsala BioCenter, Department of Molecular Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Marina Klemenčič
- Faculty of Chemistry and Chemical Technology, Department of Chemistry and Biochemistry, University of Ljubljana, Ljubljana, Slovenia
- Department of Chemistry, Umeå University, Umeå, Sweden
| | | | - Jerry Ståhlberg
- Uppsala BioCenter, Department of Molecular Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Peter Bozhkov
- Uppsala BioCenter, Department of Molecular Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
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8
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Gado JE, Harrison BE, Sandgren M, Ståhlberg J, Beckham GT, Payne CM. Machine learning reveals sequence-function relationships in family 7 glycoside hydrolases. J Biol Chem 2021; 297:100931. [PMID: 34216620 PMCID: PMC8329511 DOI: 10.1016/j.jbc.2021.100931] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 06/18/2021] [Accepted: 06/29/2021] [Indexed: 11/28/2022] Open
Abstract
Family 7 glycoside hydrolases (GH7) are among the principal enzymes for cellulose degradation in nature and industrially. These enzymes are often bimodular, including a catalytic domain and carbohydrate-binding module (CBM) attached via a flexible linker, and exhibit an active site that binds cello-oligomers of up to ten glucosyl moieties. GH7 cellulases consist of two major subtypes: cellobiohydrolases (CBH) and endoglucanases (EG). Despite the critical importance of GH7 enzymes, there remain gaps in our understanding of how GH7 sequence and structure relate to function. Here, we employed machine learning to gain data-driven insights into relationships between sequence, structure, and function across the GH7 family. Machine-learning models, trained only on the number of residues in the active-site loops as features, were able to discriminate GH7 CBHs and EGs with up to 99% accuracy, demonstrating that the lengths of loops A4, B2, B3, and B4 strongly correlate with functional subtype across the GH7 family. Classification rules were derived such that specific residues at 42 different sequence positions each predicted the functional subtype with accuracies surpassing 87%. A random forest model trained on residues at 19 positions in the catalytic domain predicted the presence of a CBM with 89.5% accuracy. Our machine learning results recapitulate, as top-performing features, a substantial number of the sequence positions determined by previous experimental studies to play vital roles in GH7 activity. We surmise that the yet-to-be-explored sequence positions among the top-performing features also contribute to GH7 functional variation and may be exploited to understand and manipulate function.
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Affiliation(s)
- Japheth E Gado
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA; Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Brent E Harrison
- Department of Computer Science, University of Kentucky, Lexington, Kentucky, USA
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Gregg T Beckham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Christina M Payne
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA.
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9
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Levenfors JJ, Nord C, Bjerketorp J, Ståhlberg J, Larsson R, Guss B, Öberg B, Broberg A. Antibacterial pyrrolidinyl and piperidinyl substituted 2,4-diacetylphloroglucinols from Pseudomonas protegens UP46. J Antibiot (Tokyo) 2020; 73:739-747. [PMID: 32439988 DOI: 10.1038/s41429-020-0318-1] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/24/2020] [Accepted: 04/28/2020] [Indexed: 12/12/2022]
Abstract
In the search for new antibiotic compounds, fractionation of Pseudomonas protegens UP46 culture extracts afforded several known Pseudomonas compounds, including 2,4-diacetylphloroglucinol (DAPG), as well as two new antibacterial alkaloids, 6-(pyrrolidin-2-yl)DAPG (1) and 6-(piperidin-2-yl)DAPG (2). The structures of 1 and 2 were determined by nuclear magnetic resonance spectroscopy and mass spectrometry. Compounds 1 and 2 were found to have antibacterial activity against the Gram-positive bacteria Staphylococcus aureus and Bacillus cereus, with minimal inhibitory concentration (MIC) 2 and 4 μg ml-1, respectively, for 1, and 2 μg ml-1 for both pathogens for 2. The MICs for 1 and 2, against all tested Gram-negative bacteria, were >32 μg ml-1. The half maximal inhibitory concentrations against HepG2 cells for compounds 1 and 2 were 11 and 18 μg ml-1, respectively, which suggested 1 and 2 be too toxic for further evaluation as possible new antibacterial drugs. Stable isotope labelling experiments showed the pyrrolidinyl group of 1 to originate from ornithine and the piperidinyl group of 2 to originate from lysine. The P. protegens acetyl transferase (PpATase) is involved in the biosynthesis of monoacetylphloroglucinol and DAPG. No optical rotation was detected for 1 or 2, and a possible reason for this was investigated by studying if the PpATase may catalyse a stereo-non-specific introduction of the pyrrolidinyl/piperidinyl group in 1 and 2, but unless the PpATase can be subjected to major conformational changes, the enzyme cannot be involved in this reaction. The PpATase is, however, likely to catalyse the formation of 2,4,6-triacetylphloroglucinol from DAPG.
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Affiliation(s)
- Jolanta J Levenfors
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07, Uppsala, Sweden.,Ultupharma AB, Södra Rudbecksgatan 13, SE-752 36, Uppsala, Sweden
| | - Christina Nord
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07, Uppsala, Sweden
| | - Joakim Bjerketorp
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07, Uppsala, Sweden.,Ultupharma AB, Södra Rudbecksgatan 13, SE-752 36, Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07, Uppsala, Sweden
| | - Rolf Larsson
- Department of Medical Sciences, Uppsala University, SE-751 85, Uppsala, Sweden
| | - Bengt Guss
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, P.O. Box 7036, SE-750 07, Uppsala, Sweden
| | - Bo Öberg
- Ultupharma AB, Södra Rudbecksgatan 13, SE-752 36, Uppsala, Sweden.,Department of Medicinal Chemistry, Uppsala University, P.O. Box 574, SE-751 23, Uppsala, Sweden
| | - Anders Broberg
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07, Uppsala, Sweden.
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10
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Bharadwaj VS, Knott BC, Ståhlberg J, Beckham GT, Crowley MF. Reply to Cosgrove: Non-enzymatic action of expansins. J Biol Chem 2020; 295:6783. [DOI: 10.1074/jbc.rl120.013432] [Citation(s) in RCA: 0] [Impact Index Per Article: 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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11
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Minina EA, Staal J, Alvarez VE, Berges JA, Berman-Frank I, Beyaert R, Bidle KD, Bornancin F, Casanova M, Cazzulo JJ, Choi CJ, Coll NS, Dixit VM, Dolinar M, Fasel N, Funk C, Gallois P, Gevaert K, Gutierrez-Beltran E, Hailfinger S, Klemenčič M, Koonin EV, Krappmann D, Linusson A, Machado MFM, Madeo F, Megeney LA, Moschou PN, Mottram JC, Nyström T, Osiewacz HD, Overall CM, Pandey KC, Ruland J, Salvesen GS, Shi Y, Smertenko A, Stael S, Ståhlberg J, Suárez MF, Thome M, Tuominen H, Van Breusegem F, van der Hoorn RAL, Vardi A, Zhivotovsky B, Lam E, Bozhkov PV. Classification and Nomenclature of Metacaspases and Paracaspases: No More Confusion with Caspases. Mol Cell 2020; 77:927-929. [PMID: 32142688 PMCID: PMC7325697 DOI: 10.1016/j.molcel.2019.12.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [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: 10/24/2019] [Revised: 12/16/2019] [Accepted: 12/23/2019] [Indexed: 01/19/2023]
Affiliation(s)
- Elena A Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden; COS, Heidelberg University, Heidelberg, Germany.
| | - Jens Staal
- VIB Center for Inflammation Research, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Vanina E Alvarez
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martin, San Martin, Buenos Aires, Argentina
| | - John A Berges
- Department of Biological Sciences and School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Ilana Berman-Frank
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Israel
| | - Rudi Beyaert
- VIB Center for Inflammation Research, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Kay D Bidle
- Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA
| | | | - Magali Casanova
- Aix-Marseille Univ, CNRS, LISM, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Juan J Cazzulo
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martin, San Martin, Buenos Aires, Argentina
| | - Chang Jae Choi
- The University of Texas at Austin, Marine Science Institute, Port Aransas, TX, USA
| | - Nuria S Coll
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra, Barcelona, Spain
| | - Vishva M Dixit
- Department of Physiological Chemistry, Genentech, South San Francisco, CA, USA
| | - Marko Dolinar
- University of Ljubljana, Faculty of Chemistry and Chemical Technology, Ljubljana, Slovenia
| | - Nicolas Fasel
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | | | - Patrick Gallois
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Kris Gevaert
- VIB Center for Medical Biotechnology, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Emilio Gutierrez-Beltran
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - Stephan Hailfinger
- Interfaculty Institute for Biochemistry, Eberhard Karls University, Tübingen, Germany
| | - Marina Klemenčič
- University of Ljubljana, Faculty of Chemistry and Chemical Technology, Ljubljana, Slovenia
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, USA
| | - Daniel Krappmann
- Research Unit Cellular Signal Integration, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
| | - Anna Linusson
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Maurício F M Machado
- Interdisciplinary Center for Biochemical Research, University of Mogi das Cruzes, Mogi das Cruzes, Brazil
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, BioTechMed Graz, Graz, Austria
| | - Lynn A Megeney
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute and Departments of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Panagiotis N Moschou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Greece; Department of Biology, University of Crete, Greece; Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Jeremy C Mottram
- York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | - Thomas Nyström
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, Gothenburg, Sweden
| | - Heinz D Osiewacz
- Institute for Molecular Biosciences, Faculty of Biosciences, Goethe University, Frankfurt/Main, Germany
| | - Christopher M Overall
- Departments of Oral Biological and Medical Sciences and Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Kailash C Pandey
- Protein Biochemistry and Engineering Laboratory, ICMR-National Institute of Malaria Research, New Delhi, India
| | - Jürgen Ruland
- Institute of Clinical Chemistry and Pathobiochemistry, School of Medicine, Technical University of Munich, Munich, Germany; German Cancer Consortium (DKTK), partner site Munich, Germany; German Center for Infection Research (DZIF), partner site Munich, Germany
| | - Guy S Salvesen
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Yigong Shi
- School of Life Sciences, Westlake University, Xihu District, Hangzhou Zhejiang Province, China
| | - Andrei Smertenko
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Simon Stael
- VIB Center for Medical Biotechnology, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, VIB-UGent Center for Plant Systems Biology, Ghent, Belgium
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - María Fernanda Suárez
- Departamento de Biologia Molecular y Bioquimica, Facultad de Ciencias, Universidad de Malaga, Campus de Teatinos, Malaga, Spain
| | - Margot Thome
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Hannele Tuominen
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, VIB-UGent Center for Plant Systems Biology, Ghent, Belgium
| | | | - Assaf Vardi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Boris Zhivotovsky
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Faculty of Fundamental Medicine, MV Lomonosov Moscow State University, Moscow, Russia
| | - Eric Lam
- Department of Plant Biology, Rutgers, The State University of New Jersey, New Brunswick, NJ USA
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden.
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12
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Bharadwaj VS, Knott BC, Ståhlberg J, Beckham GT, Crowley MF. The hydrolysis mechanism of a GH45 cellulase and its potential relation to lytic transglycosylase and expansin function. J Biol Chem 2020; 295:4477-4487. [PMID: 32054684 DOI: 10.1074/jbc.ra119.011406] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 10/08/2019] [Revised: 02/12/2020] [Indexed: 11/06/2022] Open
Abstract
Family 45 glycoside hydrolases (GH45) are endoglucanases that are integral to cellulolytic secretomes, and their ability to break down cellulose has been successfully exploited in textile and detergent industries. In addition to their industrial relevance, understanding the molecular mechanism of GH45-catalyzed hydrolysis is of fundamental importance because of their structural similarity to cell wall-modifying enzymes such as bacterial lytic transglycosylases (LTs) and expansins present in bacteria, plants, and fungi. Our understanding of the catalytic itinerary of GH45s has been incomplete because a crystal structure with substrate spanning the -1 to +1 subsites is currently lacking. Here we constructed and validated a putative Michaelis complex in silico and used it to elucidate the hydrolytic mechanism in a GH45, Cel45A from the fungus Humicola insolens, via unbiased simulation approaches. These molecular simulations revealed that the solvent-exposed active-site architecture results in lack of coordination for the hydroxymethyl group of the substrate at the -1 subsite. This lack of coordination imparted mobility to the hydroxymethyl group and enabled a crucial hydrogen bond with the catalytic acid during and after the reaction. This suggests the possibility of a nonhydrolytic reaction mechanism when the catalytic base aspartic acid is missing, as is the case in some LTs (murein transglycosylase A) and expansins. We calculated reaction free energies and demonstrate the thermodynamic feasibility of the hydrolytic and nonhydrolytic reaction mechanisms. Our results provide molecular insights into the hydrolysis mechanism in HiCel45A, with possible implications for elucidating the elusive catalytic mechanism in LTs and expansins.
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Affiliation(s)
- Vivek S Bharadwaj
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Brandon C Knott
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P. O. Box 7015, 750 07 Uppsala, Sweden
| | - Gregg T Beckham
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Michael F Crowley
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
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13
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Vermaas JV, Kont R, Beckham GT, Crowley MF, Gudmundsson M, Sandgren M, Ståhlberg J, Väljamäe P, Knott BC. The Dissociation Mechanism of the Processive Cellulase TrCel7A. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2916] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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14
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Hamark C, Pendrill R, Landström J, Dotson Fagerström A, Sandgren M, Ståhlberg J, Widmalm G. Enantioselective Binding of Propranolol and Analogues Thereof to Cellobiohydrolase Cel7A. Chemistry 2018; 24:17975-17985. [PMID: 30255965 DOI: 10.1002/chem.201803104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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: 06/18/2018] [Indexed: 12/28/2022]
Abstract
At the catalytic site for the hydrolysis of cellulose the enzyme cellobiohydrolase Cel7A binds the enantiomers of the adrenergic beta-blocker propranolol with different selectivity. Methyl-to-hydroxymethyl group modifications of propranolol, which result in higher affinity and improved selectivity, were herein studied by 1 H,1 H and 1 H,13 C scalar spin-spin coupling constants as well as utilizing the nuclear Overhauser effect (NOE) in conjunction with molecular dynamics simulations of the ligands per se, which showed the presence of all-antiperiplanar conformations, except for the one containing a vicinal oxygen-oxygen arrangement governed by the gauche effect. For the ligand-protein complexes investigated by NMR spectroscopy using, inter alia, transferred NOESY and saturation-transfer difference (STD) NMR experiments the S-isomers were shown to bind with a higher affinity and a conformation similar to that preferred in solution, in contrast to the R-isomer. The fact that the S-form of the propranolol enantiomer is pre-arranged for binding to the protein is also observed for a crystal structure of dihydroxy-(S)-propranolol and Cel7A presented herein. Whereas the binding of propranolol is entropy driven, the complexation with the dihydroxy analogue is anticipated to be favored also by an enthalpic term, such as for its enantiomer, that is, dihydroxy-(R)-propranolol, because hydrogen-bond donation replaces the corresponding bonding from hydroxyl groups in glucosyl residues of the natural substrate. In addition to a favorable entropy component, albeit lesser in magnitude, this represents an effect of enthalpy-to-entropy compensation in ligand-protein interactions.
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Affiliation(s)
- Christoffer Hamark
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691, Stockholm, Sweden
| | - Robert Pendrill
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691, Stockholm, Sweden
| | - Jens Landström
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691, Stockholm, Sweden
| | | | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 75007, Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 75007, Uppsala, Sweden
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691, Stockholm, Sweden
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15
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Liu B, Krishnaswamyreddy S, Muraleedharan MN, Olson Å, Broberg A, Ståhlberg J, Sandgren M. Side-by-side biochemical comparison of two lytic polysaccharide monooxygenases from the white-rot fungus Heterobasidion irregulare on their activity against crystalline cellulose and glucomannan. PLoS One 2018; 13:e0203430. [PMID: 30183773 PMCID: PMC6124812 DOI: 10.1371/journal.pone.0203430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [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: 07/08/2018] [Accepted: 08/21/2018] [Indexed: 11/18/2022] Open
Abstract
Our comparative studies reveal that the two lytic polysaccharide monooxygenases HiLPMO9B and HiLPMO9I from the white-rot conifer pathogen Heterobasidion irregulare display clear difference with respect to their activity against crystalline cellulose and glucomannan. HiLPMO9I produced very little soluble sugar on bacterial microcrystalline cellulose (BMCC). In contrast, HiLPMO9B was much more active against BMCC and even released more soluble sugar than the H. irregulare cellobiohydrolase I, HiCel7A. Furthermore, HiLPMO9B was shown to cooperate with and stimulate the activity of HiCel7A, both when the BMCC was first pretreated with HiLPMO9B, as well as when HiLPMO9B and HiCel7A were added together. No such stimulation was shown by HiLPMO9I. On the other hand, HiLPMO9I was shown to degrade glucomannan, using a C4-oxidizing mechanism, whereas no oxidative cleavage activity of glucomannan was detected for HiLPMO9B. Structural modeling and comparison with other glucomannan-active LPMOs suggest that conserved sugar-interacting residues on the L2, L3 and LC loops may be essential for glucomannan binding, where 4 out of 7 residues are shared by HiLPMO9I, but only one is found in HiLPMO9B. The difference shown between these two H. irregulare LPMOs may reflect distinct biological roles of these enzymes within deconstruction of different plant cell wall polysaccharides during fungal colonization of softwood.
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Affiliation(s)
- Bing Liu
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Madhu Nair Muraleedharan
- Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Åke Olson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anders Broberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
- * E-mail:
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16
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Abstract
The inverting glycoside hydrolase Trichoderma reesei (Hypocrea jecorina) Cel6A is a promising candidate for protein engineering for more economical production of biofuels. Until recently, its catalytic mechanism had been uncertain: The best candidate residue to serve as a catalytic base, Asp-175, is farther from the glycosidic cleavage site than in other glycoside hydrolase enzymes. Recent unbiased transition path sampling simulations revealed the hydrolytic mechanism for this more distant base, employing a water wire; however, it is not clear why the enzyme employs a more distant catalytic base, a highly conserved feature among homologs across different kingdoms. In this work, we describe molecular dynamics simulations designed to uncover how a base with a longer side chain, as in a D175E mutant, affects procession and active site alignment in the Michaelis complex. We show that the hydrogen bond network is tuned to the shorter aspartate side chain, and that a longer glutamate side chain inhibits procession as well as being less likely to adopt a catalytically productive conformation. Furthermore, we draw comparisons between the active site in Trichoderma reesei Cel6A and another inverting, processive cellulase to deduce the contribution of the water wire to the overall enzyme function, revealing that the more distant catalytic base enhances product release. Our results can inform efforts in the study and design of enzymes by demonstrating how counterintuitive sacrifices in chemical reactivity can have worthwhile benefits for other steps in the catalytic cycle.
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Affiliation(s)
- Tucker Burgin
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, 48109
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
| | - Heather B Mayes
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, 48109.
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17
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Borisova AS, Eneyskaya EV, Jana S, Badino SF, Kari J, Amore A, Karlsson M, Hansson H, Sandgren M, Himmel ME, Westh P, Payne CM, Kulminskaya AA, Ståhlberg J. Correlation of structure, function and protein dynamics in GH7 cellobiohydrolases from Trichoderma atroviride, T. reesei and T. harzianum. Biotechnol Biofuels 2018; 11:5. [PMID: 29344086 PMCID: PMC5766984 DOI: 10.1186/s13068-017-1006-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/23/2017] [Indexed: 05/11/2023]
Abstract
BACKGROUND The ascomycete fungus Trichoderma reesei is the predominant source of enzymes for industrial conversion of lignocellulose. Its glycoside hydrolase family 7 cellobiohydrolase (GH7 CBH) TreCel7A constitutes nearly half of the enzyme cocktail by weight and is the major workhorse in the cellulose hydrolysis process. The orthologs from Trichoderma atroviride (TatCel7A) and Trichoderma harzianum (ThaCel7A) show high sequence identity with TreCel7A, ~ 80%, and represent naturally evolved combinations of cellulose-binding tunnel-enclosing loop motifs, which have been suggested to influence intrinsic cellobiohydrolase properties, such as endo-initiation, processivity, and off-rate. RESULTS The TatCel7A, ThaCel7A, and TreCel7A enzymes were characterized for comparison of function. The catalytic domain of TatCel7A was crystallized, and two structures were determined: without ligand and with thio-cellotriose in the active site. Initial hydrolysis of bacterial cellulose was faster with TatCel7A than either ThaCel7A or TreCel7A. In synergistic saccharification of pretreated corn stover, both TatCel7A and ThaCel7A were more efficient than TreCel7A, although TatCel7A was more sensitive to thermal inactivation. Structural analyses and molecular dynamics (MD) simulations were performed to elucidate important structure/function correlations. Moreover, reverse conservation analysis (RCA) of sequence diversity revealed divergent regions of interest located outside the cellulose-binding tunnel of Trichoderma spp. GH7 CBHs. CONCLUSIONS We hypothesize that the combination of loop motifs is the main determinant for the observed differences in Cel7A activity on cellulosic substrates. Fine-tuning of the loop flexibility appears to be an important evolutionary target in Trichoderma spp., a conclusion supported by the RCA data. Our results indicate that, for industrial use, it would be beneficial to combine loop motifs from TatCel7A with the thermostability features of TreCel7A. Furthermore, one region implicated in thermal unfolding is suggested as a primary target for protein engineering.
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Affiliation(s)
- Anna S. Borisova
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
- B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute”, Orlova Roscha, Gatchina, Leningrad Region 188300 Russia
| | - Elena V. Eneyskaya
- B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute”, Orlova Roscha, Gatchina, Leningrad Region 188300 Russia
| | - Suvamay Jana
- Department of Chemical and Materials Engineering, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, KY 40506-0046 USA
| | - Silke F. Badino
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
| | - Jeppe Kari
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
| | - Antonella Amore
- National Renewable Energy Laboratory, Biosciences Center, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Magnus Karlsson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, 750 07 Uppsala, Sweden
| | - Henrik Hansson
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
| | - Michael E. Himmel
- National Renewable Energy Laboratory, Biosciences Center, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Peter Westh
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
| | - Christina M. Payne
- Department of Chemical and Materials Engineering, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, KY 40506-0046 USA
- Present Address: Division of Chemical, Bioengineering, Environmental, and Transport Systems, National Science Foundation, Alexandria, VA USA
| | - Anna A. Kulminskaya
- B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute”, Orlova Roscha, Gatchina, Leningrad Region 188300 Russia
- Department of Medical Physics, Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
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18
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Goedegebuur F, Dankmeyer L, Gualfetti P, Karkehabadi S, Hansson H, Jana S, Huynh V, Kelemen BR, Kruithof P, Larenas EA, Teunissen PJM, Ståhlberg J, Payne CM, Mitchinson C, Sandgren M. Improving the thermal stability of cellobiohydrolase Cel7A from Hypocrea jecorina by directed evolution. J Biol Chem 2017; 292:17418-17430. [PMID: 28860192 DOI: 10.1074/jbc.m117.803270] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [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: 06/26/2017] [Revised: 08/24/2017] [Indexed: 11/06/2022] Open
Abstract
Secreted mixtures of Hypocrea jecorina cellulases are able to efficiently degrade cellulosic biomass to fermentable sugars at large, commercially relevant scales. H. jecorina Cel7A, cellobiohydrolase I, from glycoside hydrolase family 7, is the workhorse enzyme of the process. However, the thermal stability of Cel7A limits its use to processes where temperatures are no higher than 50 °C. Enhanced thermal stability is desirable to enable the use of higher processing temperatures and to improve the economic feasibility of industrial biomass conversion. Here, we enhanced the thermal stability of Cel7A through directed evolution. Sites with increased thermal stability properties were combined, and a Cel7A variant (FCA398) was obtained, which exhibited a 10.4 °C increase in Tm and a 44-fold greater half-life compared with the wild-type enzyme. This Cel7A variant contains 18 mutated sites and is active under application conditions up to at least 75 °C. The X-ray crystal structure of the catalytic domain was determined at 2.1 Å resolution and showed that the effects of the mutations are local and do not introduce major backbone conformational changes. Molecular dynamics simulations revealed that the catalytic domain of wild-type Cel7A and the FCA398 variant exhibit similar behavior at 300 K, whereas at elevated temperature (475 and 525 K), the FCA398 variant fluctuates less and maintains more native contacts over time. Combining the structural and dynamic investigations, rationales were developed for the stabilizing effect at many of the mutated sites.
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Affiliation(s)
- Frits Goedegebuur
- From DuPont Industrial Biosciences, Archimedesweg 30, Leiden 2333CN, The Netherlands,
| | - Lydia Dankmeyer
- From DuPont Industrial Biosciences, Archimedesweg 30, Leiden 2333CN, The Netherlands
| | | | - Saeid Karkehabadi
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, Uppsala SE-75007, Sweden, and
| | - Henrik Hansson
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, Uppsala SE-75007, Sweden, and
| | - Suvamay Jana
- the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506
| | - Vicky Huynh
- DuPont Industrial Biosciences, Palo Alto, California 94304
| | | | - Paulien Kruithof
- From DuPont Industrial Biosciences, Archimedesweg 30, Leiden 2333CN, The Netherlands
| | | | | | - Jerry Ståhlberg
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, Uppsala SE-75007, Sweden, and
| | - Christina M Payne
- the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506
| | | | - Mats Sandgren
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, Uppsala SE-75007, Sweden, and
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19
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Chylenski P, Forsberg Z, Ståhlberg J, Várnai A, Lersch M, Bengtsson O, Sæbø S, Horn SJ, Eijsink VGH. Development of minimal enzyme cocktails for hydrolysis of sulfite-pulped lignocellulosic biomass. J Biotechnol 2017; 246:16-23. [PMID: 28219736 DOI: 10.1016/j.jbiotec.2017.02.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/26/2017] [Accepted: 02/13/2017] [Indexed: 01/02/2023]
Abstract
Despite recent progress, saccharification of lignocellulosic biomass is still a major cost driver in biorefining. In this study, we present the development of minimal enzyme cocktails for hydrolysis of Norway spruce and sugarcane bagasse, which were pretreated using the so-called BALI™ process, which is based on sulfite pulping technology. Minimal enzyme cocktails were composed using several glycoside hydrolases purified from the industrially relevant filamentous fungus Trichoderma reesei and a purified commercial β-glucosidase from Aspergillus niger. The contribution of in-house expressed lytic polysaccharide monooxygenases (LPMOs) was also tested, since oxidative cleavage of cellulose by such LPMOs is known to be beneficial for conversion efficiency. We show that the optimized cocktails permit efficient saccharification at reasonable enzyme loadings and that the effect of the LPMOs is substrate-dependent. Using a cocktail comprising only four enzymes, glucan conversion for Norway spruce reached >80% at enzyme loadings of 8mg/g glucan, whereas almost 100% conversion was achieved at 16mg/g.
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Affiliation(s)
- Piotr Chylenski
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Zarah Forsberg
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anikó Várnai
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | | | | | - Solve Sæbø
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Svein Jarle Horn
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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20
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Mayes HB, Knott BC, Crowley MF, Broadbelt LJ, Ståhlberg J, Beckham GT. Who's on base? Revealing the catalytic mechanism of inverting family 6 glycoside hydrolases. Chem Sci 2016; 7:5955-5968. [PMID: 30155195 PMCID: PMC6091422 DOI: 10.1039/c6sc00571c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [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: 02/05/2016] [Accepted: 05/29/2016] [Indexed: 12/16/2022] Open
Abstract
In several important classes of inverting carbohydrate-active enzymes, the identity of the catalytic base remains elusive, including in family 6 Glycoside Hydrolase (GH6) enzymes, which are key components of cellulase cocktails for cellulose depolymerization. Despite many structural and kinetic studies with both wild-type and mutant enzymes, especially on the Trichoderma reesei (Hypocrea jecorina) GH6 cellulase (TrCel6A), the catalytic base in the single displacement inverting mechanism has not been definitively identified in the GH6 family. Here, we employ transition path sampling to gain insight into the catalytic mechanism, which provides unbiased atomic-level understanding of key order parameters involved in cleaving the strong glycosidic bond. Our hybrid quantum mechanics and molecular mechanics (QM/MM) simulations reveal a network of hydrogen bonding that aligns two active site water molecules that play key roles in hydrolysis: one water molecule drives the reaction by nucleophilic attack on the substrate and a second shuttles a proton to the putative base (D175) via a short water wire. We also investigated the case where the putative base is mutated to an alanine, an enzyme that is experimentally still partially active. The simulations predict that proton hopping along a water wire via a Grotthuss mechanism provides a mechanism of catalytic rescue. Further simulations reveal that substrate processive motion is 'driven' by strong electrostatic interactions with the protein at the product sites and that the -1 sugar adopts a 2SO ring configuration as it reaches its binding site. This work thus elucidates previously elusive steps in the processive catalytic mechanism of this important class of enzymes.
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Affiliation(s)
- Heather B Mayes
- Department of Chemical and Biological Engineering , Northwestern University , Evanston , IL 60208 , USA
- National Bioenergy Center , National Renewable Energy Laboratory , Golden , CO 80401 , USA .
| | - Brandon C Knott
- National Bioenergy Center , National Renewable Energy Laboratory , Golden , CO 80401 , USA .
| | - Michael F Crowley
- Biosciences Center , National Renewable Energy Laboratory , Golden , CO 80401 , USA
| | - Linda J Broadbelt
- Department of Chemical and Biological Engineering , Northwestern University , Evanston , IL 60208 , USA
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology , Swedish University of Agricultural Sciences , SE-75007 , Uppsala , Sweden .
| | - Gregg T Beckham
- National Bioenergy Center , National Renewable Energy Laboratory , Golden , CO 80401 , USA .
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21
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Borisova AS, Eneyskaya EV, Bobrov KS, Jana S, Logachev A, Polev DE, Lapidus AL, Ibatullin FM, Saleem U, Sandgren M, Payne CM, Kulminskaya AA, Ståhlberg J. Sequencing, biochemical characterization, crystal structure and molecular dynamics of cellobiohydrolase Cel7A from
Geotrichum candidum
3C. FEBS J 2015; 282:4515-37. [DOI: 10.1111/febs.13509] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/13/2015] [Accepted: 09/04/2015] [Indexed: 01/01/2023]
Affiliation(s)
- Anna S. Borisova
- Department of Chemistry and Biotechnology Swedish University of Agricultural Sciences Uppsala Sweden
- National Research Centre «Kurchatov Institute» B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Orlova roscha Russia
| | - Elena V. Eneyskaya
- National Research Centre «Kurchatov Institute» B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Orlova roscha Russia
| | - Kirill S. Bobrov
- National Research Centre «Kurchatov Institute» B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Orlova roscha Russia
| | - Suvamay Jana
- Department of Chemical and Materials Engineering University of Kentucky Lexington KY USA
| | - Anton Logachev
- Theodosius Dobzhansky Center for Genome Bioinformatics St. Petersburg State University Russia
| | - Dmitrii E. Polev
- Research Resource Centre «Molecular and Cell Technologies» St. Petersburg State University Russia
| | - Alla L. Lapidus
- Centre for Algorithmic Biotechnology St. Petersburg Academic University Russia
| | - Farid M. Ibatullin
- National Research Centre «Kurchatov Institute» B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Orlova roscha Russia
| | - Umair Saleem
- Department of Chemistry and Biotechnology Swedish University of Agricultural Sciences Uppsala Sweden
| | - Mats Sandgren
- Department of Chemistry and Biotechnology Swedish University of Agricultural Sciences Uppsala Sweden
| | - Christina M. Payne
- Department of Chemical and Materials Engineering University of Kentucky Lexington KY USA
| | - Anna A. Kulminskaya
- National Research Centre «Kurchatov Institute» B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Orlova roscha Russia
- Department of Medical Physics Peter the Great St. Petersburg Polytechnic University Russia
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology Swedish University of Agricultural Sciences Uppsala Sweden
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22
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Momeni MH, Ubhayasekera W, Sandgren M, Ståhlberg J, Hansson H. Structural insights into the inhibition of cellobiohydrolase Cel7A by xylo-oligosaccharides. FEBS J 2015; 282:2167-77. [PMID: 25765184 DOI: 10.1111/febs.13265] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [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: 01/02/2015] [Revised: 03/06/2015] [Accepted: 03/10/2015] [Indexed: 11/28/2022]
Abstract
UNLABELLED The filamentous fungus Hypocrea jecorina (anamorph of Trichoderma reesei) is the predominant source of enzymes for industrial saccharification of lignocellulose biomass. The major enzyme, cellobiohydrolase Cel7A, constitutes nearly half of the total protein in the secretome. The performance of such enzymes is susceptible to inhibition by compounds liberated by physico-chemical pre-treatment if the biomass is kept unwashed. Xylan and xylo-oligosaccharides (XOS) have been proposed to play a key role in inhibition of cellobiohydrolases of glycoside hydrolase family 7. To elucidate the mechanism behind this inhibition at a molecular level, we used X-ray crystallography to determine structures of H. jecorina Cel7A in complex with XOS. Structures with xylotriose, xylotetraose and xylopentaose revealed a predominant binding mode at the entrance of the substrate-binding tunnel of the enzyme, in which each xylose residue is shifted ~ 2.4 Å towards the catalytic center compared with binding of cello-oligosaccharides. Furthermore, partial occupancy of two consecutive xylose residues at subsites -2 and -1 suggests an alternative binding mode for XOS in the vicinity of the catalytic center. Interestingly, the -1 xylosyl unit exhibits an open aldehyde conformation in one of the structures and a ring-closed pyranoside in another complex. Complementary inhibition studies with p-nitrophenyl lactoside as substrate indicate mixed inhibition rather than pure competitive inhibition. DATABASE The atomic coordinates and structure factors are available in the Protein Data Bank under accession number 4D5I (H. jecorina Cel7A E212Q variant, complex with xylotriose), 4D5J (H. jecorina Cel7A E217Q variant, complex with xylotriose), 4D5O (H. jecorina Cel7A E212Q variant, complex with xylopentaose), 4D5P (H. jecorina Cel7A E217Q variant, complex with xylopentaose), 4D5Q (wild-type H. jecorina Cel7A, complex with xylopentaose) and 4D5V (H. jecorina Cel7A E217Q variant, complex with xylotetraose).
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Affiliation(s)
- Majid Haddad Momeni
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Wimal Ubhayasekera
- Institute of Medicinal Chemistry, University of Copenhagen, Denmark.,MAX-Lab, Lund University, Sweden
| | - Mats Sandgren
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Henrik Hansson
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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23
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Affiliation(s)
- Christina M. Payne
- Department
of Chemical and Materials Engineering and Center for Computational
Sciences, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, Kentucky 40506, United States
| | - Brandon C. Knott
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
| | - Heather B. Mayes
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Henrik Hansson
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Michael E. Himmel
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Mats Sandgren
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Jerry Ståhlberg
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Gregg T. Beckham
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
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24
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Tiukova IA, de Barros Pita W, Sundell D, Haddad Momeni M, Horn SJ, Ståhlberg J, de Morais MA, Passoth V. Adaptation of Dekkera bruxellensis to lignocellulose-based substrate. Biotechnol Appl Biochem 2014; 61:51-7. [PMID: 23941546 DOI: 10.1002/bab.1145] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [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: 04/09/2013] [Accepted: 07/18/2013] [Indexed: 11/10/2022]
Abstract
Adaptation of Dekkera bruxellensis to lignocellulose hydrolysate was investigated. Cells of D. bruxellensis were grown for 72 and 192 H in batch and continuous culture, respectively (adapted cells). Cultivations in semisynthetic medium were run as controls (nonadapted cells). To test the adaptation, cells from these cultures were reinoculated in the lignocellulose medium, and growth and ethanol production characteristics were monitored. Cells adapted to lignocellulose hydrolysate had a shorter lag phase, grew faster, and produced a higher ethanol concentration as compared with nonadapted cells. A stability test showed that after cultivation in rich medium, cells partially lost the adapted phenotype but still showed faster growth and higher ethanol production as compared with nonadapted cells. Because alcohol dehydrogenase genes have been described to be involved in the adaptation to furfural in Saccharomyces cerevisiae, an analogous mechanism of adaptation to lignocelluloses hydrolysate of D. bruxellensis was hypothesized. However, gene expression analysis showed that genes homologous to S. cerevisiae ADH1 were not involved in the adaptation to lignocelluloses hydrolysate in D. bruxellensis.
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Affiliation(s)
- Ievgeniia A Tiukova
- Uppsala Biocenter, Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025750 07, Uppsala, Sweden
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25
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Momeni MH, Goedegebuur F, Hansson H, Karkehabadi S, Askarieh G, Mitchinson C, Larenas EA, Ståhlberg J, Sandgren M. Expression, crystal structure and cellulase activity of the thermostable cellobiohydrolase Cel7A from the fungus Humicola grisea var. thermoidea. ACTA ACUST UNITED AC 2014; 70:2356-66. [PMID: 25195749 PMCID: PMC4157447 DOI: 10.1107/s1399004714013844] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/13/2014] [Indexed: 11/11/2022]
Abstract
Glycoside hydrolase family 7 (GH7) cellobiohydrolases (CBHs) play a key role in biomass recycling in nature. They are typically the most abundant enzymes expressed by potent cellulolytic fungi, and are also responsible for the majority of hydrolytic potential in enzyme cocktails for industrial processing of plant biomass. The thermostability of the enzyme is an important parameter for industrial utilization. In this study, Cel7 enzymes from different fungi were expressed in a fungal host and assayed for thermostability, including Hypocrea jecorina Cel7A as a reference. The most stable of the homologues, Humicola grisea var. thermoidea Cel7A, exhibits a 10°C higher melting temperature (T(m) of 72.5°C) and showed a 4-5 times higher initial hydrolysis rate than H. jecorina Cel7A on phosphoric acid-swollen cellulose and showed the best performance of the tested enzymes on pretreated corn stover at elevated temperature (65°C, 24 h). The enzyme shares 57% sequence identity with H. jecorina Cel7A and consists of a GH7 catalytic module connected by a linker to a C-terminal CBM1 carbohydrate-binding module. The crystal structure of the H. grisea var. thermoidea Cel7A catalytic module (1.8 Å resolution; R(work) and R(free) of 0.16 and 0.21, respectively) is similar to those of other GH7 CBHs. The deviations of several loops along the cellulose-binding path between the two molecules in the asymmetric unit indicate higher flexibility than in the less thermostable H. jecorina Cel7A.
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Affiliation(s)
- Majid Haddad Momeni
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Frits Goedegebuur
- DuPont, Industrial Biosciences, Archimedesweg 30, 2333 CN Leiden, The Netherlands
| | - Henrik Hansson
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Saeid Karkehabadi
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Glareh Askarieh
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Colin Mitchinson
- DuPont, Industrial Biosciences, Page Mill Road, Palo Alto, CA 94304, USA
| | - Edmundo A Larenas
- DuPont, Industrial Biosciences, Page Mill Road, Palo Alto, CA 94304, USA
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Mats Sandgren
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
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26
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Knott BC, Crowley MF, Himmel ME, Ståhlberg J, Beckham GT. Carbohydrate-protein interactions that drive processive polysaccharide translocation in enzymes revealed from a computational study of cellobiohydrolase processivity. J Am Chem Soc 2014; 136:8810-9. [PMID: 24869982 DOI: 10.1021/ja504074g] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Translocation of carbohydrate polymers through protein tunnels and clefts is a ubiquitous biochemical phenomenon in proteins such as polysaccharide synthases, glycoside hydrolases, and carbohydrate-binding modules. Although static snapshots of carbohydrate polymer binding in proteins have long been studied via crystallography and spectroscopy, the molecular details of polysaccharide chain processivity have not been elucidated. Here, we employ simulation to examine how a cellulose chain translocates by a disaccharide unit during the processive cycle of a glycoside hydrolase family 7 cellobiohydrolase. Our results demonstrate that these biologically and industrially important enzymes employ a two-step mechanism for chain threading to form a Michaelis complex and that the free energy barrier to chain threading is significantly lower than the hydrolysis barrier. Taken with previous studies, our findings suggest that the rate-limiting step in enzymatic cellulose degradation is the glycosylation reaction, not chain processivity. Based on the simulations, we find that strong electrostatic interactions with polar residues that are conserved in GH7 cellobiohydrolases, but not in GH7 endoglucanases, at the leading glucosyl ring provide the thermodynamic driving force for polysaccharide chain translocation. Also, we consider the role of aromatic-carbohydrate interactions, which are widespread in carbohydrate-active enzymes and have long been associated with processivity. Our analysis suggests that the primary role for these aromatic residues is to provide tunnel shape and guide the carbohydrate chain to the active site. More broadly, this work elucidates the role of common protein motifs found in carbohydrate-active enzymes that synthesize or depolymerize polysaccharides by chain translocation mechanisms coupled to catalysis.
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Affiliation(s)
- Brandon C Knott
- National Bioenergy Center and ‡Biosciences Center, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
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27
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Gudmundsson M, Kim S, Wu M, Ishida T, Momeni MH, Vaaje-Kolstad G, Lundberg D, Royant A, Ståhlberg J, Eijsink VGH, Beckham GT, Sandgren M. Structural and electronic snapshots during the transition from a Cu(II) to Cu(I) metal center of a lytic polysaccharide monooxygenase by X-ray photoreduction. J Biol Chem 2014; 289:18782-92. [PMID: 24828494 DOI: 10.1074/jbc.m114.563494] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [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: 01/28/2023] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are a recently discovered class of enzymes that employ a copper-mediated, oxidative mechanism to cleave glycosidic bonds. The LPMO catalytic mechanism likely requires that molecular oxygen first binds to Cu(I), but the oxidation state in many reported LPMO structures is ambiguous, and the changes in the LPMO active site required to accommodate both oxidation states of copper have not been fully elucidated. Here, a diffraction data collection strategy minimizing the deposited x-ray dose was used to solve the crystal structure of a chitin-specific LPMO from Enterococcus faecalis (EfaCBM33A) in the Cu(II)-bound form. Subsequently, the crystalline protein was photoreduced in the x-ray beam, which revealed structural changes associated with the conversion from the initial Cu(II)-oxidized form with two coordinated water molecules, which adopts a trigonal bipyramidal geometry, to a reduced Cu(I) form in a T-shaped geometry with no coordinated water molecules. A comprehensive survey of Cu(II) and Cu(I) structures in the Cambridge Structural Database unambiguously shows that the geometries observed in the least and most reduced structures reflect binding of Cu(II) and Cu(I), respectively. Quantum mechanical calculations of the oxidized and reduced active sites reveal little change in the electronic structure of the active site measured by the active site partial charges. Together with a previous theoretical investigation of a fungal LPMO, this suggests significant functional plasticity in LPMO active sites. Overall, this study provides molecular snapshots along the reduction process to activate the LPMO catalytic machinery and provides a general method for solving LPMO structures in both copper oxidation states.
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Affiliation(s)
- Mikael Gudmundsson
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Seonah Kim
- the National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Miao Wu
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Takuya Ishida
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden, the Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Majid Hadadd Momeni
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Gustav Vaaje-Kolstad
- the Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, NO-1432 Ås, Norway
| | - Daniel Lundberg
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Antoine Royant
- the Institut de Biologie Structurale, Université Grenoble Alpes-CNRS-CEA, 38042 Grenoble, France, and the European Synchrotron Radiation Facility, 38000 Grenoble, France
| | - Jerry Ståhlberg
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden, the Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, NO-1432 Ås, Norway
| | - Vincent G H Eijsink
- the Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, NO-1432 Ås, Norway
| | - Gregg T Beckham
- the National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401,
| | - Mats Sandgren
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden,
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28
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Knott BC, Haddad Momeni M, Crowley MF, Mackenzie LF, Götz AW, Sandgren M, Withers SG, Ståhlberg J, Beckham GT. The Mechanism of Cellulose Hydrolysis by a Two-Step, Retaining Cellobiohydrolase Elucidated by Structural and Transition Path Sampling Studies. J Am Chem Soc 2013; 136:321-9. [DOI: 10.1021/ja410291u] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
| | - Majid Haddad Momeni
- Department
of Molecular Biology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | | | - Lloyd F. Mackenzie
- Department
of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - Andreas W. Götz
- San
Diego Supercomputer Center, University of California San Diego, La Jolla, California 92093, United States
| | - Mats Sandgren
- Department
of Molecular Biology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Stephen G. Withers
- Department
of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - Jerry Ståhlberg
- Department
of Molecular Biology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
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29
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Wu M, Bu L, Vuong TV, Wilson DB, Crowley MF, Sandgren M, Ståhlberg J, Beckham GT, Hansson H. Loop motions important to product expulsion in the Thermobifida fusca glycoside hydrolase family 6 cellobiohydrolase from structural and computational studies. J Biol Chem 2013; 288:33107-17. [PMID: 24085303 DOI: 10.1074/jbc.m113.502765] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellobiohydrolases (CBHs) are typically major components of natural enzyme cocktails for biomass degradation. Their active sites are enclosed in a tunnel, enabling processive hydrolysis of cellulose chains. Glycoside hydrolase Family 6 (GH6) CBHs act from nonreducing ends by an inverting mechanism and are present in many cellulolytic fungi and bacteria. The bacterial Thermobifida fusca Cel6B (TfuCel6B) exhibits a longer and more enclosed active site tunnel than its fungal counterparts. Here, we determine the structures of two TfuCel6B mutants co-crystallized with cellobiose, D274A (catalytic acid), and the double mutant D226A/S232A, which targets the putative catalytic base and a conserved serine that binds the nucleophilic water. The ligand binding and the structure of the active site are retained when compared with the wild type structure, supporting the hypothesis that these residues are directly involved in catalysis. One structure exhibits crystallographic waters that enable construction of a model of the α-anomer product after hydrolysis. Interestingly, the product sites of TfuCel6B are completely enclosed by an "exit loop" not present in fungal GH6 CBHs and by an extended "bottom loop". From the structures, we hypothesize that either of the loops enclosing the product subsites in the TfuCel6B active site tunnel must open substantially for product release. With simulation, we demonstrate that both loops can readily open to allow product release with equal probability in solution or when the enzyme is engaged on cellulose. Overall, this study reveals new structural details of GH6 CBHs likely important for functional differences among enzymes from this important family.
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Affiliation(s)
- Miao Wu
- From the Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
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30
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Payne CM, Resch MG, Chen L, Crowley MF, Himmel ME, Taylor LE, Sandgren M, Ståhlberg J, Stals I, Tan Z, Beckham GT. Glycosylated linkers in multimodular lignocellulose-degrading enzymes dynamically bind to cellulose. Proc Natl Acad Sci U S A 2013; 110:14646-51. [PMID: 23959893 PMCID: PMC3767562 DOI: 10.1073/pnas.1309106110] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Plant cell-wall polysaccharides represent a vast source of food in nature. To depolymerize polysaccharides to soluble sugars, many organisms use multifunctional enzyme mixtures consisting of glycoside hydrolases, lytic polysaccharide mono-oxygenases, polysaccharide lyases, and carbohydrate esterases, as well as accessory, redox-active enzymes for lignin depolymerization. Many of these enzymes that degrade lignocellulose are multimodular with carbohydrate-binding modules (CBMs) and catalytic domains connected by flexible, glycosylated linkers. These linkers have long been thought to simply serve as a tether between structured domains or to act in an inchworm-like fashion during catalytic action. To examine linker function, we performed molecular dynamics (MD) simulations of the Trichoderma reesei Family 6 and Family 7 cellobiohydrolases (TrCel6A and TrCel7A, respectively) bound to cellulose. During these simulations, the glycosylated linkers bind directly to cellulose, suggesting a previously unknown role in enzyme action. The prediction from the MD simulations was examined experimentally by measuring the binding affinity of the Cel7A CBM and the natively glycosylated Cel7A CBM-linker. On crystalline cellulose, the glycosylated linker enhances the binding affinity over the CBM alone by an order of magnitude. The MD simulations before and after binding of the linker also suggest that the bound linker may affect enzyme action due to significant damping in the enzyme fluctuations. Together, these results suggest that glycosylated linkers in carbohydrate-active enzymes, which are intrinsically disordered proteins in solution, aid in dynamic binding during the enzymatic deconstruction of plant cell walls.
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Affiliation(s)
- Christina M. Payne
- Biosciences Center and
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506
| | | | - Liqun Chen
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80303
| | | | | | | | - Mats Sandgren
- Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
| | - Ingeborg Stals
- Faculty of Applied Bioscience Engineering, University College Ghent, 9000 Ghent, Belgium
- Department of Biochemistry and Molecular Biology, Ghent University, 9000 Ghent, Belgium; and
| | - Zhongping Tan
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80303
| | - Gregg T. Beckham
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401
- Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401
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Wu M, Beckham GT, Larsson AM, Ishida T, Kim S, Payne CM, Himmel ME, Crowley MF, Horn SJ, Westereng B, Igarashi K, Samejima M, Ståhlberg J, Eijsink VGH, Sandgren M. Crystal structure and computational characterization of the lytic polysaccharide monooxygenase GH61D from the Basidiomycota fungus Phanerochaete chrysosporium. J Biol Chem 2013; 288:12828-39. [PMID: 23525113 PMCID: PMC3642327 DOI: 10.1074/jbc.m113.459396] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [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: 02/06/2013] [Revised: 03/15/2013] [Indexed: 01/11/2023] Open
Abstract
Carbohydrate structures are modified and degraded in the biosphere by a myriad of mostly hydrolytic enzymes. Recently, lytic polysaccharide mono-oxygenases (LPMOs) were discovered as a new class of enzymes for cleavage of recalcitrant polysaccharides that instead employ an oxidative mechanism. LPMOs employ copper as the catalytic metal and are dependent on oxygen and reducing agents for activity. LPMOs are found in many fungi and bacteria, but to date no basidiomycete LPMO has been structurally characterized. Here we present the three-dimensional crystal structure of the basidiomycete Phanerochaete chrysosporium GH61D LPMO, and, for the first time, measure the product distribution of LPMO action on a lignocellulosic substrate. The structure reveals a copper-bound active site common to LPMOs, a collection of aromatic and polar residues near the binding surface that may be responsible for regio-selectivity, and substantial differences in loop structures near the binding face compared with other LPMO structures. The activity assays indicate that this LPMO primarily produces aldonic acids. Last, molecular simulations reveal conformational changes, including the binding of several regions to the cellulose surface, leading to alignment of three tyrosine residues on the binding face of the enzyme with individual cellulose chains, similar to what has been observed for family 1 carbohydrate-binding modules. A calculated potential energy surface for surface translation indicates that P. chrysosporium GH61D exhibits energy wells whose spacing seems adapted to the spacing of cellobiose units along a cellulose chain.
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Affiliation(s)
- Miao Wu
- From the Department of Molecular Biology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-750 07 Uppsala, Sweden
| | - Gregg T. Beckham
- the National Bioenergy Center and
- the Department of Chemical Engineering, Colorado School of Mines, Golden, Colorado 80401
| | - Anna M. Larsson
- From the Department of Molecular Biology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-750 07 Uppsala, Sweden
| | - Takuya Ishida
- the Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | | | - Christina M. Payne
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
- the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, and
| | - Michael E. Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Michael F. Crowley
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Svein J. Horn
- the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Bjørge Westereng
- the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Kiyohiko Igarashi
- the Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Masahiro Samejima
- the Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Jerry Ståhlberg
- From the Department of Molecular Biology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-750 07 Uppsala, Sweden
| | - Vincent G. H. Eijsink
- From the Department of Molecular Biology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-750 07 Uppsala, Sweden
| | - Mats Sandgren
- From the Department of Molecular Biology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-750 07 Uppsala, Sweden
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32
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Passoth V, Tabassum MR, Nair HA, Olstorpe M, Tiukova I, Ståhlberg J. Enhanced ethanol production from wheat straw by integrated storage and pre-treatment (ISP). Enzyme Microb Technol 2013; 52:105-10. [DOI: 10.1016/j.enzmictec.2012.11.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 11/05/2012] [Accepted: 11/06/2012] [Indexed: 10/27/2022]
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Sandgren M, Wu M, Karkehabadi S, Mitchinson C, Kelemen BR, Larenas EA, Ståhlberg J, Hansson H. The Structure of a Bacterial Cellobiohydrolase: The Catalytic Core of the Thermobifida fusca Family GH6 Cellobiohydrolase Cel6B. J Mol Biol 2013; 425:622-35. [DOI: 10.1016/j.jmb.2012.11.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 11/26/2012] [Accepted: 11/28/2012] [Indexed: 10/27/2022]
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Momeni MH, Payne CM, Hansson H, Mikkelsen NE, Svedberg J, Engström Å, Sandgren M, Beckham GT, Ståhlberg J. Structural, biochemical, and computational characterization of the glycoside hydrolase family 7 cellobiohydrolase of the tree-killing fungus Heterobasidion irregulare. J Biol Chem 2013; 288:5861-72. [PMID: 23303184 DOI: 10.1074/jbc.m112.440891] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Root rot fungi of the Heterobasidion annosum complex are the most damaging pathogens in temperate forests, and the recently sequenced Heterobasidion irregulare genome revealed over 280 carbohydrate-active enzymes. Here, H. irregulare was grown on biomass, and the most abundant protein in the culture filtrate was identified as the only family 7 glycoside hydrolase in the genome, which consists of a single catalytic domain, lacking a linker and carbohydrate-binding module. The enzyme, HirCel7A, was characterized biochemically to determine the optimal conditions for activity. HirCel7A was crystallized and the structure, refined at 1.7 Å resolution, confirms that HirCel7A is a cellobiohydrolase rather than an endoglucanase, with a cellulose-binding tunnel that is more closed than Phanerochaete chrysosporium Cel7D and more open than Hypocrea jecorina Cel7A, suggesting intermediate enzyme properties. Molecular simulations were conducted to ascertain differences in enzyme-ligand interactions, ligand solvation, and loop flexibility between the family 7 glycoside hydrolase cellobiohydrolases from H. irregulare, H. jecorina, and P. chrysosporium. The structural comparisons and simulations suggest significant differences in enzyme-ligand interactions at the tunnel entrance in the -7 to -4 binding sites and suggest that a tyrosine residue at the tunnel entrance of HirCel7A may serve as an additional ligand-binding site. Additionally, the loops over the active site in H. jecorina Cel7A are more closed than loops in the other two enzymes, which has implications for the degree of processivity, endo-initiation, and substrate dissociation. Overall, this study highlights molecular level features important to understanding this biologically and industrially important family of glycoside hydrolases.
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Affiliation(s)
- Majid Haddad Momeni
- Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-751 24 Uppsala, Sweden
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Wu M, Nerinckx W, Piens K, Ishida T, Hansson H, Sandgren M, Ståhlberg J. Rational design, synthesis, evaluation and enzyme-substrate structures of improved fluorogenic substrates for family 6 glycoside hydrolases. FEBS J 2012; 280:184-98. [DOI: 10.1111/febs.12060] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 10/31/2012] [Accepted: 11/05/2012] [Indexed: 11/29/2022]
Affiliation(s)
- Miao Wu
- Department of Molecular Biology; Swedish University of Agricultural Sciences; Uppsala; Sweden
| | - Wim Nerinckx
- Laboratory for Protein Biochemistry and Biomolecular Engineering; Department of Biochemistry and Microbiology; University of Gent; Gent; Belgium
| | | | - Takuya Ishida
- Department of Molecular Biology; Swedish University of Agricultural Sciences; Uppsala; Sweden
| | - Henrik Hansson
- Department of Molecular Biology; Swedish University of Agricultural Sciences; Uppsala; Sweden
| | - Mats Sandgren
- Department of Molecular Biology; Swedish University of Agricultural Sciences; Uppsala; Sweden
| | - Jerry Ståhlberg
- Department of Molecular Biology; Swedish University of Agricultural Sciences; Uppsala; Sweden
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36
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Olson Å, Aerts A, Asiegbu F, Belbahri L, Bouzid O, Broberg A, Canbäck B, Coutinho PM, Cullen D, Dalman K, Deflorio G, van Diepen LTA, Dunand C, Duplessis S, Durling M, Gonthier P, Grimwood J, Fossdal CG, Hansson D, Henrissat B, Hietala A, Himmelstrand K, Hoffmeister D, Högberg N, James TY, Karlsson M, Kohler A, Kües U, Lee YH, Lin YC, Lind M, Lindquist E, Lombard V, Lucas S, Lundén K, Morin E, Murat C, Park J, Raffaello T, Rouzé P, Salamov A, Schmutz J, Solheim H, Ståhlberg J, Vélëz H, de Vries RP, Wiebenga A, Woodward S, Yakovlev I, Garbelotto M, Martin F, Grigoriev IV, Stenlid J. Insight into trade-off between wood decay and parasitism from the genome of a fungal forest pathogen. New Phytol 2012; 194:1001-1013. [PMID: 22463738 DOI: 10.1111/j.1469-8137.2012.04128.x] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Parasitism and saprotrophic wood decay are two fungal strategies fundamental for succession and nutrient cycling in forest ecosystems. An opportunity to assess the trade-off between these strategies is provided by the forest pathogen and wood decayer Heterobasidion annosum sensu lato. We report the annotated genome sequence and transcript profiling, as well as the quantitative trait loci mapping, of one member of the species complex: H. irregulare. Quantitative trait loci critical for pathogenicity, and rich in transposable elements, orphan and secreted genes, were identified. A wide range of cellulose-degrading enzymes are expressed during wood decay. By contrast, pathogenic interaction between H. irregulare and pine engages fewer carbohydrate-active enzymes, but involves an increase in pectinolytic enzymes, transcription modules for oxidative stress and secondary metabolite production. Our results show a trade-off in terms of constrained carbohydrate decomposition and membrane transport capacity during interaction with living hosts. Our findings establish that saprotrophic wood decay and necrotrophic parasitism involve two distinct, yet overlapping, processes.
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Affiliation(s)
- Åke Olson
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
| | - Andrea Aerts
- US DOE Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Fred Asiegbu
- Department of Forest Ecology, PO Box 27 Latokartanonkaari 7, 00014 University of Helsinki, Helsinki, Finland
| | - Lassaad Belbahri
- Laboratory of Soil Biology, University of Neuchâtel, Rue Emile Argand 11, CH-2000 Neuchâtel, Switzerland
| | - Ourdia Bouzid
- Microbiology, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Anders Broberg
- Department of Chemistry, Swedish University of Agricultural Sciences, Box 7015, 750 05 Uppsala, Sweden
| | - Björn Canbäck
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
| | - Pedro M Coutinho
- AFMB UMR 6098 CNRS/UI/UII, Case 932, 163 Avenue de Luminy 13288 Marseille cedex 9, France
| | - Dan Cullen
- Forest Products Laboratory, Madison, WI 53726, USA
| | - Kerstin Dalman
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
| | - Giuliana Deflorio
- Department of Plant and Soil Science, Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen, AB24 3UU, Scotland UK
| | - Linda T A van Diepen
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Christophe Dunand
- Laboratory of Cell Surfaces and Plant Signalisation 24, University Paul Sabatier (Toulouse III), UMR5546- CNRS, Chemin de Borde-Rouge, BP 42617, Auzeville 31326 Castanet-Tolosan, France
| | - Sébastien Duplessis
- UMR INRA-UHP 'Interactions Arbres/Micro-Organismes' IFR 110 'Genomique, Ecophysiologie et Ecologie Fonctionnelles' INRA-Nancy 54280 Champenoux, France
| | - Mikael Durling
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
| | - Paolo Gonthier
- Department of Exploitation and Protection of Agricultural and Forest Resources (Di. Va. P. R. A.) - Plant Pathology, University of Torino, Via L. da Vinci 44, I-10095 Grugliasco, Italy
| | - Jane Grimwood
- HudsonAlpha Institute for Biotechnology, 601 Genome Way Huntsville, AL 35806, USA
| | - Carl Gunnar Fossdal
- Norwegian Forest and Landscape Institute, Høgskoleveien 8, NO-1432 Ås, Norway
| | - David Hansson
- Department of Chemistry, Swedish University of Agricultural Sciences, Box 7015, 750 05 Uppsala, Sweden
| | - Bernard Henrissat
- AFMB UMR 6098 CNRS/UI/UII, Case 932, 163 Avenue de Luminy 13288 Marseille cedex 9, France
| | - Ari Hietala
- Norwegian Forest and Landscape Institute, Høgskoleveien 8, NO-1432 Ås, Norway
| | - Kajsa Himmelstrand
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
| | - Dirk Hoffmeister
- Pharmaceutical Biology, Friedrich-Schiller-Universität Jena, Winzerlaer Str. 2, 07745 Jena, Germany
| | - Nils Högberg
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Magnus Karlsson
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
| | - Annegret Kohler
- UMR INRA-UHP 'Interactions Arbres/Micro-Organismes' IFR 110 'Genomique, Ecophysiologie et Ecologie Fonctionnelles' INRA-Nancy 54280 Champenoux, France
| | - Ursula Kües
- Büsgen-Institute, Section Molecular Wood Biotechnology and Technical Mycology, University of Göttingen, Büsgenweg 2, D-37077 Göttingen, Germany
| | - Yong-Hwan Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
| | - Yao-Cheng Lin
- VIB Department of Plant Systems Biology, Ghent University, Bioinformatics and Evolutionary Genomics, Technologiepark 927, B-9052 Gent, Belgium
| | - Mårten Lind
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
| | | | - Vincent Lombard
- AFMB UMR 6098 CNRS/UI/UII, Case 932, 163 Avenue de Luminy 13288 Marseille cedex 9, France
| | - Susan Lucas
- US DOE Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Karl Lundén
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
| | - Emmanuelle Morin
- UMR INRA-UHP 'Interactions Arbres/Micro-Organismes' IFR 110 'Genomique, Ecophysiologie et Ecologie Fonctionnelles' INRA-Nancy 54280 Champenoux, France
| | - Claude Murat
- UMR INRA-UHP 'Interactions Arbres/Micro-Organismes' IFR 110 'Genomique, Ecophysiologie et Ecologie Fonctionnelles' INRA-Nancy 54280 Champenoux, France
| | - Jongsun Park
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
| | - Tommaso Raffaello
- Department of Forest Ecology, PO Box 27 Latokartanonkaari 7, 00014 University of Helsinki, Helsinki, Finland
| | - Pierre Rouzé
- VIB Department of Plant Systems Biology, Ghent University, Bioinformatics and Evolutionary Genomics, Technologiepark 927, B-9052 Gent, Belgium
| | - Asaf Salamov
- US DOE Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Jeremy Schmutz
- HudsonAlpha Institute for Biotechnology, 601 Genome Way Huntsville, AL 35806, USA
| | - Halvor Solheim
- Norwegian Forest and Landscape Institute, Høgskoleveien 8, NO-1432 Ås, Norway
| | - Jerry Ståhlberg
- Department of Molecular Biology, Swedish University of Agricultural Sciences, Box 590, Husargatan 3, 751 24 Uppsala, Sweden
| | - Heriberto Vélëz
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
| | - Ronald P de Vries
- Microbiology, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
- CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Ad Wiebenga
- CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Steve Woodward
- Department of Plant and Soil Science, Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen, AB24 3UU, Scotland UK
| | - Igor Yakovlev
- Norwegian Forest and Landscape Institute, Høgskoleveien 8, NO-1432 Ås, Norway
| | | | - Francis Martin
- UMR INRA-UHP 'Interactions Arbres/Micro-Organismes' IFR 110 'Genomique, Ecophysiologie et Ecologie Fonctionnelles' INRA-Nancy 54280 Champenoux, France
| | | | - Jan Stenlid
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Ullsväg 26, 750 05 Uppsala, Sweden
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Bu L, Nimlos MR, Shirts MR, Ståhlberg J, Himmel ME, Crowley MF, Beckham GT. Product binding varies dramatically between processive and nonprocessive cellulase enzymes. J Biol Chem 2012; 287:24807-13. [PMID: 22648408 DOI: 10.1074/jbc.m112.365510] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellulases hydrolyze β-1,4 glycosidic linkages in cellulose, which are among the most prevalent and stable bonds in Nature. Cellulases comprise many glycoside hydrolase families and exist as processive or nonprocessive enzymes. Product inhibition negatively impacts cellulase action, but experimental measurements of product-binding constants vary significantly, and there is little consensus on the importance of this phenomenon. To provide molecular level insights into cellulase product inhibition, we examine the impact of product binding on processive and nonprocessive cellulases by calculating the binding free energy of cellobiose to the product sites of catalytic domains of processive and nonprocessive enzymes from glycoside hydrolase families 6 and 7. The results suggest that cellobiose binds to processive cellulases much more strongly than nonprocessive cellulases. We also predict that the presence of a cellodextrin bound in the reactant site of the catalytic domain, which is present during enzymatic catalysis, has no effect on product binding in nonprocessive cellulases, whereas it significantly increases product binding to processive cellulases. This difference in product binding correlates with hydrogen bonding between the substrate-side ligand and the cellobiose product in processive cellulase tunnels and the additional stabilization from the longer tunnel-forming loops. The hydrogen bonds between the substrate- and product-side ligands are disrupted by water in nonprocessive cellulase clefts, and the lack of long tunnel-forming loops results in lower affinity of the product ligand. These findings provide new insights into the large discrepancies reported for binding constants for cellulases and suggest that product inhibition will vary significantly based on the amount of productive binding for processive cellulases on cellulose.
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Affiliation(s)
- Lintao Bu
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
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Westereng B, Ishida T, Vaaje-Kolstad G, Wu M, Eijsink VGH, Igarashi K, Samejima M, Ståhlberg J, Horn SJ, Sandgren M. The putative endoglucanase PcGH61D from Phanerochaete chrysosporium is a metal-dependent oxidative enzyme that cleaves cellulose. PLoS One 2011; 6:e27807. [PMID: 22132148 PMCID: PMC3223205 DOI: 10.1371/journal.pone.0027807] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 10/25/2011] [Indexed: 12/02/2022] Open
Abstract
Many fungi growing on plant biomass produce proteins currently classified as glycoside hydrolase family 61 (GH61), some of which are known to act synergistically with cellulases. In this study we show that PcGH61D, the gene product of an open reading frame in the genome of Phanerochaete chrysosporium, is an enzyme that cleaves cellulose using a metal-dependent oxidative mechanism that leads to generation of aldonic acids. The activity of this enzyme and its beneficial effect on the efficiency of classical cellulases are stimulated by the presence of electron donors. Experiments with reduced cellulose confirmed the oxidative nature of the reaction catalyzed by PcGH61D and indicated that the enzyme may be capable of penetrating into the substrate. Considering the abundance of GH61-encoding genes in fungi and genes encoding their functional bacterial homologues currently classified as carbohydrate binding modules family 33 (CBM33), this enzyme activity is likely to turn out as a major determinant of microbial biomass-degrading efficiency.
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Affiliation(s)
- Bjørge Westereng
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Takuya Ishida
- Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
- Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Gustav Vaaje-Kolstad
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Miao Wu
- Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Vincent G. H. Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Kiyohiko Igarashi
- Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Masahiro Samejima
- Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Jerry Ståhlberg
- Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Svein J. Horn
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Mats Sandgren
- Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Blomqvist J, South E, Tiukova I, Tiukova L, Momeni MH, Hansson H, Ståhlberg J, Horn SJ, Schnürer J, Passoth V. Fermentation of lignocellulosic hydrolysate by the alternative industrial ethanol yeast Dekkera bruxellensis. Lett Appl Microbiol 2011; 53:73-8. [PMID: 21535044 DOI: 10.1111/j.1472-765x.2011.03067.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [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
AIM Testing the ability of the alternative ethanol production yeast Dekkera bruxellensis to produce ethanol from lignocellulose hydrolysate and comparing it to Saccharomyces cerevisiae. METHODS AND RESULTS Industrial isolates of D. bruxellensis and S. cerevisiae were cultivated in small-scale batch fermentations of enzymatically hydrolysed steam exploded aspen sawdust. Different dilutions of hydrolysate were tested. None of the yeasts grew in undiluted or 1:2 diluted hydrolysate [final glucose concentration always adjusted to 40 g l⁻¹ (0.22 mol l⁻¹)]. This was most likely due to the presence of inhibitors such as acetate or furfural. In 1:5 hydrolysate, S. cerevisiae grew, but not D. bruxellensis, and in 1:10 hydrolysate, both yeasts grew. An external vitamin source (e.g. yeast extract) was essential for growth of D. bruxellensis in this lignocellulosic hydrolysate and strongly stimulated S. cerevisiae growth and ethanol production. Ethanol yields of 0.42 ± 0.01 g ethanol (g glucose)⁻¹ were observed for both yeasts in 1:10 hydrolysate. In small-scale continuous cultures with cell recirculation, with a gradual increase in the hydrolysate concentration, D. bruxellensis was able to grow in 1:5 hydrolysate. In bioreactor experiments with cell recirculation, hydrolysate contents were increased up to 1:2 hydrolysate, without significant losses in ethanol yields for both yeasts and only slight differences in viable cell counts, indicating an ability of both yeasts to adapt to toxic compounds in the hydrolysate. CONCLUSIONS Dekkera bruxellensis and S. cerevisiae have a similar potential to ferment lignocellulose hydrolysate to ethanol and to adapt to fermentation inhibitors in the hydrolysate. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first study investigating the potential of D. bruxellensis to ferment lignocellulosic hydrolysate. Its high competitiveness in industrial fermentations makes D. bruxellensis an interesting alternative for ethanol production from those substrates.
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Affiliation(s)
- J Blomqvist
- Department of Microbiology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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Dererie DY, Trobro S, Momeni MH, Hansson H, Blomqvist J, Passoth V, Schnürer A, Sandgren M, Ståhlberg J. Improved bio-energy yields via sequential ethanol fermentation and biogas digestion of steam exploded oat straw. Bioresour Technol 2011; 102:4449-55. [PMID: 21256738 DOI: 10.1016/j.biortech.2010.12.096] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 12/22/2010] [Accepted: 12/23/2010] [Indexed: 05/11/2023]
Abstract
Using standard laboratory equipment, thermochemically pretreated oat straw was enzymatically saccharified and fermented to ethanol, and after removal of ethanol the remaining material was subjected to biogas digestion. A detailed mass balance calculation shows that, for steam explosion pretreatment, this combined ethanol fermentation and biogas digestion converts 85-87% of the higher heating value (HHV) of holocellulose (cellulose and hemicellulose) in the oat straw into biofuel energy. The energy (HHV) yield of the produced ethanol and methane was 9.5-9.8 MJ/(kg dry oat straw), which is 28-34% higher than direct biogas digestion that yielded 7.3-7.4 MJ/(kg dry oat straw). The rate of biogas formation from the fermentation residues was also higher than from the corresponding pretreated but unfermented oat straw, indicating that the biogas digestion could be terminated after only 24 days. This suggests that the ethanol process acts as an additional pretreatment for the biogas process.
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Affiliation(s)
- Debebe Yilma Dererie
- Department of Molecular Biology, Swedish University of Agricultural Sciences, P.O. Box 590, SE-751 24 Uppsala, Sweden
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Lantz SE, Goedegebuur F, Hommes R, Kaper T, Kelemen BR, Mitchinson C, Wallace L, Ståhlberg J, Larenas EA. Hypocrea jecorina CEL6A protein engineering. Biotechnol Biofuels 2010; 3:20. [PMID: 20822549 PMCID: PMC2945327 DOI: 10.1186/1754-6834-3-20] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 09/08/2010] [Indexed: 05/03/2023]
Abstract
The complex technology of converting lignocellulose to fuels such as ethanol has advanced rapidly over the past few years, and enzymes are a critical component of this technology. The production of effective enzyme systems at cost structures that facilitate commercial processes has been the focus of research for many years. Towards this end, the H. jecorina cellobiohydrolases, CEL7A and CEL6A, have been the subject of protein engineering at Genencor. Our first rounds of cellobiohydrolase engineering were directed towards improving the thermostability of both of these enzymes and produced variants of CEL7A and CEL6A with apparent melting temperatures above 70°C, placing their stability on par with that of H. jecorina CEL5A (EG2) and CEL3A (BGL1). We have now moved towards improving CEL6A- and CEL7A-specific performance in the context of a complete enzyme system under industrially relevant conditions. Achievement of these goals required development of new screening strategies and tools. We discuss these advances along with some results, focusing mainly on engineering of CEL6A.
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Affiliation(s)
- Suzanne E Lantz
- Genencor Division, Danisco USA Inc., 925 Page Mill Rd. Palo Alto, CA 94304, USA
| | - Frits Goedegebuur
- Genencor, a Danisco Division, Archimedesweg 30, 2333CN, Leiden, The Netherlands
| | - Ronald Hommes
- Genencor, a Danisco Division, Archimedesweg 30, 2333CN, Leiden, The Netherlands
| | - Thijs Kaper
- Genencor Division, Danisco USA Inc., 925 Page Mill Rd. Palo Alto, CA 94304, USA
| | - Bradley R Kelemen
- Genencor Division, Danisco USA Inc., 925 Page Mill Rd. Palo Alto, CA 94304, USA
| | - Colin Mitchinson
- Genencor Division, Danisco USA Inc., 925 Page Mill Rd. Palo Alto, CA 94304, USA
| | - Louise Wallace
- Genencor Division, Danisco USA Inc., 925 Page Mill Rd. Palo Alto, CA 94304, USA
| | - Jerry Ståhlberg
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-751 24 Uppsala, Sweden
| | - Edmundo A Larenas
- Genencor Division, Danisco USA Inc., 925 Page Mill Rd. Palo Alto, CA 94304, USA
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Vasur J, Kawai R, Jonsson KHM, Widmalm G, Engström Å, Frank M, Andersson E, Hansson H, Forsberg Z, Igarashi K, Samejima M, Sandgren M, Ståhlberg J. Synthesis of Cyclic β-Glucan Using Laminarinase 16A Glycosynthase Mutant from the Basidiomycete Phanerochaete chrysosporium. J Am Chem Soc 2010; 132:1724-30. [DOI: 10.1021/ja909129b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Jonas Vasur
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Rie Kawai
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - K. Hanna M. Jonsson
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Göran Widmalm
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Åke Engström
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Martin Frank
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Evalena Andersson
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Henrik Hansson
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Zarah Forsberg
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Kiyohiko Igarashi
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Masahiro Samejima
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Mats Sandgren
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
| | - Jerry Ståhlberg
- Department of Molecular Biology, Swedish University of Agricultural Sciences, POB 590, SE-754 21 Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, The University of Tokyo, Japan, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, and Molecular Structural Analysis, German Cancer Research Center, INF 280,
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Passoth V, Eriksson A, Sandgren M, Ståhlberg J, Piens K, Schnürer J. Airtight storage of moist wheat grain improves bioethanol yields. Biotechnol Biofuels 2009; 2:16. [PMID: 19695089 PMCID: PMC2733301 DOI: 10.1186/1754-6834-2-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 08/20/2009] [Indexed: 05/28/2023]
Abstract
BACKGROUND Drying is currently the most frequently used conservation method for cereal grain, which in temperate climates consumes a major part of process energy. Airtight storage of moist feed grain using the biocontrol yeast Pichia anomala as biopreservation agent can substantially reduce the process energy for grain storage. In this study we tested the potential of moist stored grain for bioethanol production. RESULTS The ethanol yield from moist wheat was enhanced by 14% compared with the control obtained from traditionally (dry) stored grain. This enhancement was observed independently of whether or not P. anomala was added to the storage system, indicating that P. anomala does not impair ethanol fermentation. Starch and sugar analyses showed that during pre-treatment the starch of moist grain was better degraded by amylase treatment than that of the dry grain. Additional pre-treatment with cellulose and hemicellulose-degrading enzymes did not further increase the total ethanol yield. Sugar analysis after this pre-treatment showed an increased release of sugars not fermentable by Saccharomyces cerevisiae. CONCLUSION The ethanol yield from wheat grain is increased by airtight storage of moist grain, which in addition can save substantial amounts of energy used for drying the grain. This provides a new opportunity to increase the sustainability of bioethanol production.
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Affiliation(s)
- Volkmar Passoth
- Uppsala Biocenter, Department of Microbiology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Anna Eriksson
- Uppsala Biocenter, Department of Microbiology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
- Chematur Engineering, SE-691 27 Karlskoga, Sweden
| | - Mats Sandgren
- Uppsala Biocenter, Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-751 24 Uppsala, Sweden
| | - Jerry Ståhlberg
- Uppsala Biocenter, Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-751 24 Uppsala, Sweden
| | - Kathleen Piens
- Laboratory for Protein Biochemistry and Biomolecular Engineering, Department of Biochemistry and Microbiology, Ghent University, 9000 Ghent, Belgium
| | - Johan Schnürer
- Uppsala Biocenter, Department of Microbiology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
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Vasur J, Kawai R, Andersson E, Igarashi K, Sandgren M, Samejima M, Ståhlberg J. X-ray crystal structures of Phanerochaete chrysosporium Laminarinase 16A in complex with products from lichenin and laminarin hydrolysis. FEBS J 2009; 276:3858-69. [PMID: 19769746 DOI: 10.1111/j.1742-4658.2009.07099.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The 1,3(4)-beta-D-glucanases of glycoside hydrolase family 16 provide useful examples of versatile yet specific protein-carbohydrate interactions. In the present study, we report the X-ray structures of the 1,3(4)-beta-D-glucanase Phanerochaete chrysosporium Laminarinase 16A in complex with beta-glucan products from laminarin (1.6 A) and lichenin (1.1 A) hydrolysis. The G6G3G3G glucan, in complex with the enzyme, showed a beta-1,6 branch in the acceptor site. The G4G3G ligand-protein complex showed that there was no room for a beta-1,6 branch in the -1 or -2 subsites; furthermore, the distorted residue in the -1 subsite and the glucose in the -2 subsite required a beta-1,3 bond between them. These are the first X-ray crystal structures of any 1,3(4)-beta-D-glucanase in complex with glucan products. They provide details of both substrate and product binding in support of earlier enzymatic evidence.
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Affiliation(s)
- Jonas Vasur
- Department of Molecular Biology, University of Agricultural Sciences, Uppsala, Sweden
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Vasur J, Kawai R, Larsson AM, Igarashi K, Sandgren M, Samejima M, Ståhlberg J. X-ray crystallographic native sulfur SAD structure determination of laminarinase Lam16A fromPhanerochaete chrysosporium. Acta Crystallogr D Biol Crystallogr 2006; 62:1422-9. [PMID: 17057348 DOI: 10.1107/s0907444906036407] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2006] [Accepted: 09/08/2006] [Indexed: 11/10/2022]
Abstract
Laminarinase Lam16A from Phanerochaete chrysosporium was recombinantly expressed in Pichia pastoris, crystallized and the structure was solved at 1.34 A resolution using native sulfur SAD X-ray crystallography. It is the first structure of a non-specific 1,3(4)-beta-D-glucanase from glycoside hydrolase family 16 (GH16). P. chrysosporium is a wood-degrading basidiomycete fungus and Lam16A is the predominant extracellular protein expressed when laminarin is used as the sole carbon source. The protein folds into a curved beta-sandwich homologous to those of other known GH16 enzyme structures (especially kappa-carrageenase from Pseudoalteromonas carrageenovora and beta-agarase from Zobelia galactanivorans). A notable likeness is also evident with the related glycoside hydrolase family 7 (GH7) enzymes. A mammalian lectin, p58/ERGIC, as well as polysaccharide lyase (PL7) enzymes also showed significant similarity to Lam16A. The enzyme has two potential N-glycosylation sites. One such site, at Asn43, displayed a branched heptasaccharide sufficiently stabilized to be interpreted from the X-ray diffraction data. The other N-glycosylation motif was found close to the catalytic centre and is evidently not glycosylated.
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Affiliation(s)
- Jonas Vasur
- Department of Molecular Biology, Swedish University of Agricultural Sciences, PO Box 590, SE-75124 Uppsala, Sweden
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Larsson AM, Anderson L, Xu B, Muñoz IG, Usón I, Janson JC, Stålbrand H, Ståhlberg J. Three-dimensional crystal structure and enzymic characterization of beta-mannanase Man5A from blue mussel Mytilus edulis. J Mol Biol 2006; 357:1500-10. [PMID: 16487541 DOI: 10.1016/j.jmb.2006.01.044] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [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: 10/26/2005] [Revised: 01/05/2006] [Accepted: 01/09/2006] [Indexed: 11/23/2022]
Abstract
Endo-beta-1,4-d-mannanase is the key depolymerizing enzyme for beta-1,4-mannan polymers present in the cell walls of plants and some algae, as well as in some types of plant seeds. Endo-1,4-beta-mannanase from blue mussel Mytilus edulis (MeMan5A) belongs to the glycoside hydrolase (GH) family 5 enzymes. The MeMan5A structure has been determined to 1.6A resolution using the multiple-wavelength anomalous dispersion method at the selenium K edge with selenomethionyl MeMan5A expressed in the yeast Pichia pastoris. As expected for GH 5 enzymes, the structure showed a (betaalpha)(8)-barrel fold. An unusually large number of histidine side-chains are exposed on the surface, which may relate to its location within the crystalline style of the digestive tract of the mussel. Kinetic analysis of MeMan5A revealed that the enzyme requires at least six subsites for efficient hydrolysis. Mannotetraose (M4) and mannopentaose (M5) were shown to interact with subsites -3 to +1, and -3 to +2, respectively. A clear kinetic threshold was observed when going from M4 to M5, indicating that the +2 subsite provides important interaction in the hydrolysis of short oligomeric mannose substrates. The catalytic centre motif at subsite -1 found in superfamily GH clan A is, as expected, conserved in MeMan5A, but the architecture of the catalytic cleft differs significantly from other GH 5 enzyme structures. We therefore suggest that MeMan5A represents a new subfamily in GH 5.
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Affiliation(s)
- Anna M Larsson
- Department of Cell and Molecular Biology, Uppsala University, Biomedical Center, Box 596, SE-751 24 Uppsala, Sweden
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Abstract
The cellobiohydrolase Pc_Cel7D is the major cellulase produced by the white-rot fungus Phanerochaete chrysosporium, constituting approximately 10% of the total secreted protein in liquid culture on cellulose. The enzyme is classified into family 7 of the glycoside hydrolases and, like other family members, catalyses cellulose hydrolysis with net retention of the anomeric carbon configuration. Previous work described the apo structure of the enzyme. Here we investigate the binding of the product, cellobiose, and several inhibitors, i.e. lactose, cellobioimidazole, Tris/HCl, calcium and a thio-linked substrate analogue, methyl 4-S-beta-cellobiosyl-4-thio-beta-cellobioside (GG-S-GG). The three disaccharides bind in the glucosyl-binding subsites +1 and +2, close to the exit of the cellulose-binding tunnel/cleft. Pc_Cel7D binds to lactose more strongly than cellobiose, while the opposite is true for the homologous Trichoderma reesei cellobiohydrolase Tr_Cel7A. Although both sugars bind Pc_Cel7D in a similar fashion, the different preferences can be explained by varying interactions with nearby loops. Cellobioimidazole is bound at a slightly different position, displaced approximately 2 A toward the catalytic centre. Thus the Pc_Cel7D complexes provide evidence for two binding modes of the reducing-end cellobiosyl moiety; this conclusion is confirmed by comparison with other available structures. The combined results suggest that hydrolysis of the glycosyl-enzyme intermediate may not require the prior release of the cellobiose product from the enzyme. Further, the structure obtained in the presence of both GG-S-GG and cellobiose revealed electron density for Tris at the catalytic centre. Inhibition experiments confirm that both Tris and calcium are effective inhibitors at the conditions used for crystallization.
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Affiliation(s)
- Wimal Ubhayasekera
- Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Sandgren M, Ståhlberg J, Mitchinson C. Structural and biochemical studies of GH family 12 cellulases: improved thermal stability, and ligand complexes. Prog Biophys Mol Biol 2004; 89:246-91. [PMID: 15950056 DOI: 10.1016/j.pbiomolbio.2004.11.002] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this review we will describe how we have gathered structural and biochemical information from several homologous cellulases from one class of glycoside hydrolases (GH family 12), and used this information within the framework of a protein-engineering program for the design of new variants of these enzymes. These variants have been characterized to identify some of the positions and the types of mutations in the enzymes that are responsible for some of the biochemical differences in thermal stability and activity between the homologous enzymes. In this process we have solved the three-dimensional structure of four of these homologous GH 12 cellulases: Three fungal enzymes, Humicola grisea Cel12A, Hypocrea jecorina Cel12A and Hypocrea schweinitzii Cel12A, and one bacterial, Streptomyces sp. 11AG8 Cel12A. We have also determined the three-dimensional structures of the two most stable H. jecorina Cel12A variants. In addition, four ligand-complex structures of the wild-type H. grisea Cel12A enzyme have been solved and have made it possible to characterize some of the interactions between substrate and enzyme. The structural and biochemical studies of these related GH 12 enzymes, and their variants, have provided insight on how specific residues contribute to protein thermal stability and enzyme activity. This knowledge can serve as a structural toolbox for the design of Cel12A enzymes with specific properties and features suited to existing or new applications.
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Affiliation(s)
- Mats Sandgren
- Department of Cell and Molecular Biology, Uppsala University, Biomedical Center, Husargatan 3, Box 596, SE-751 24 Uppsala, Sweden.
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Sandgren M, Berglund GI, Shaw A, Ståhlberg J, Kenne L, Desmet T, Mitchinson C. Crystal Complex Structures Reveal How Substrate is Bound in the −4 to the +2 Binding Sites of Humicola grisea Cel12A. J Mol Biol 2004; 342:1505-17. [PMID: 15364577 DOI: 10.1016/j.jmb.2004.07.098] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [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: 04/30/2004] [Revised: 07/19/2004] [Accepted: 07/30/2004] [Indexed: 11/27/2022]
Abstract
As part of an ongoing enzyme discovery program to investigate the properties and catalytic mechanism of glycoside hydrolase family 12 (GH 12) endoglucanases, a GH family that contains several cellulases that are of interest in industrial applications, we have solved four new crystal structures of wild-type Humicola grisea Cel12A in complexes formed by soaking with cellobiose, cellotetraose, cellopentaose, and a thio-linked cellotetraose derivative (G2SG2). These complex structures allow mapping of the non-covalent interactions between the enzyme and the glucosyl chain bound in subsites -4 to +2 of the enzyme, and shed light on the mechanism and function of GH 12 cellulases. The unhydrolysed cellopentaose and the G2SG2 cello-oligomers span the active site of the catalytically active H.grisea Cel12A enzyme, with the pyranoside bound in subsite -1 displaying a S31 skew boat conformation. After soaking in cellotetraose, the cello-oligomer that is found bound in site -4 to -1 contains a beta-1,3-linkage between the two cellobiose units in the oligomer, which is believed to have been formed by a transglycosylation reaction that has occurred during the ligand soak of the protein crystals. The close fit of this ligand and the binding sites occupied suggest a novel mixed beta-glucanase activity for this enzyme.
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Affiliation(s)
- Mats Sandgren
- Department of Cell and Molecular Biology, Uppsala University, Biomedical Center, Box 596, SE-751 24 Uppsala, Sweden.
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Medve J, Ståhlberg J, Tjerneld F. Adsorption and synergism of cellobiohydrolase I and II ofTrichoderma reeseiduring hydrolysis of microcrystalline cellulose. Biotechnol Bioeng 2004; 44:1064-73. [DOI: 10.1002/bit.260440907] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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