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Structure and functional studies of plant cell wall degrading enzymes

glycoside hydrolase family 3 β-glucosidases and lytic polysaccharide monooxygenases

Gudmundsson, Mikael (2014). Structure and functional studies of plant cell wall degrading enzymes. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2014:83
ISBN 978-91-576-8114-0
eISBN 978-91-576-8115-7
[Doctoral thesis]

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Abstract

Presently, plant biomass is considered as one of the major future renewable sources for the production of second-generation biofuels. While the first generation biofuels essentially are based on starch and sucrose rich feed stocks and which production may compete with food production, the second-generation biofuels may be based on lignocellulose as feedstock, which is less problematic from an ethical point of view. The degradation of carbohydrates in plant biomass to fermentable sugars requires the concerted action of several diverse classes of carbohydrate active enzymes (CAZymes) for a total and efficient conversion of the plant biomass. Through a carefully balanced synergism mechanistically different CAZymes are able to degrade the stable and recalcitrant pol- ymers in the plant cell walls, such as cellulose, to soluble and fermentable monosaccharides. It is crucial to study the properties and function of these enzymes if we want to strive for a sustainable production of chemicals and biofuels, as they serve as a reservoir of environmentally friendly molecular tools. The main focus of the research work presented in this thesis is biochemical and structure-function characterizations of two classes of CAZymes: fungal glycoside hydrolase family 3 (GH3) β-glucosidases, and bacterial lytic polysaccharide monooxygenases, often referred to as LPMOs. GH3 β- glucosidases catalyse the conversion of disaccharides, produced by other CAZymes e.g. cellulases, to glucose. H. jecorina Cel3A, R. emersonii Cel3A and N. crassa NcGH3-3 are three industrially relevant fungal GH3 β-glucosidases for which the structures have been determined using X-ray crystallographic methods. The H. jecorina Cel3A, R. em- ersonii Cel3A enzymes has also been characterized biochemically. The LPMOs act in the very initial stage of plant cell wall degradation and cleave glycosidic bonds in crys- talline polysaccharides via an oxidative mechanism, which facilitates access to new chain ends for other CAZymes. To elucidate the structural and biochemical properties of LPMOs with bacterial origin, the structure of an AA10 LPMO the LPMO10A from Enterococcus faecalis was determined using X-ray crystallography. Furthermore, structural changes of the active site metal configuration by so-called X-ray induced photoreduction, were determined. During this reduction process, which mimics the active enzyme, the bound active site copper atom is reduced from Cu(I) to Cu(II), which causes changes in the ligation configuration.

Authors/Creators:Gudmundsson, Mikael
Title:Structure and functional studies of plant cell wall degrading enzymes
Subtitle:glycoside hydrolase family 3 β-glucosidases and lytic polysaccharide monooxygenases
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :20 November 2014
Depositing date:20 November 2014
Volume:2014:83
Number of Pages:96
Papers/manuscripts:
NumberReferences
I.Karkehabadi S, Helmich KE, Kaper T, Hansson H, Mikkelsen NE, Gudmundsson M, Piens K, Fujdala M, Banerjee G, Scott-Craig JS, Walton JD, Phillips GN and Sandgren M. (2014). Biochemical Characterization and Crystal Structures of a Fungal Family 3 β-Glucosidase, Cel3A from Hypocrea jecorina. The Journal of Biological Chemistry. 289(45), 31624- 31637.
II.Gudmundsson M, Larsson AM, Hansson H, Stals I, Larenas E, Kaper T and Sandgren M. (2014). Crystal Structure of Glycoside Hydrolase Family 3 β-Glucosidase Cel3A from the Moderately Thermophilic Fungus Rasamsonia emersonii. (Submitted manuscript)
III.Gudmundsson M, Karkehabadi S, Mikkelsen NE, Kaper T, and Sandgren M. Crystal structure of a Glycoside Hydrolase Family 3 β-Glucosidase from Neurospora crassa. (Manuscript)
IV.Gudmundsson M*, Kim S*, Wu M*, Ishida T, Momeni MH, Vaaje- Kolstad G, Lundberg D, Royant A, Ståhlberg J, Eijsink VGH, Beckham GT, and Sandgren M. (2014). 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. The Journal of Biological Chemistry. 289(27), 18782–18792.
Place of Publication:Uppsala
Publisher:Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8114-0
ISBN for electronic version:978-91-576-8115-7
ISSN:1652-6880
Language:English
Additional Information:
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P06 Renewable energy resources
X Agricola extesions > X50 Chemistry
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Biochemistry and Molecular Biology
Agrovoc terms:lignocellulose, cell walls, biodegradation, beta glucosidase, hydrolases, crystallization, molecular biology
Keywords:Beta-glucosidase, Glycoside hydrolase, Lytic polysaccharide monooxygenase, Cellulose degradation, Structural biology, X-ray Crystallography
URN:NBN:urn:nbn:se:slu:epsilon-e-2233
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-2233
ID Code:11663
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Department of Chemistry and Biotechnology (140101-161231)
External funders:Energimyndigheten
Deposited By: Mikael Gudmundsson
Deposited On:21 Nov 2014 15:01
Metadata Last Modified:02 Dec 2014 11:09

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