Fowler, CA, Hemsworth, GR orcid.org/0000-0002-8226-1380, Cuskin, F et al. (5 more authors) (2018) Structure and function of a glycoside hydrolase family 8 endoxylanase from Teredinibacter turnerae. Acta Crystallographica Section D: Structural Biology, 74 (10). pp. 946-955. ISSN 2059-7983
Abstract
The biological conversion of lignocellulosic matter into high-value chemicals or biofuels is of increasing industrial importance as the sector slowly transitions away from nonrenewable sources. Many industrial processes involve the use of cellulolytic enzyme cocktails – a selection of glycoside hydrolases and, increasingly, polysaccharide oxygenases – to break down recalcitrant plant polysaccharides. ORFs from the genome of Teredinibacter turnerae, a symbiont hosted within the gills of marine shipworms, were identified in order to search for enzymes with desirable traits. Here, a putative T. turnerae glycoside hydrolase from family 8, hereafter referred to as TtGH8, is analysed. The enzyme is shown to be active against β-1,4-xylan and mixed-linkage (β-1,3,β-1,4) marine xylan. Kinetic parameters, obtained using high-performance anion-exchange chromatography with pulsed amperometric detection and 3,5-dinitrosalicyclic acid reducing-sugar assays, show that TtGH8 catalyses the hydrolysis of β-1,4-xylohexaose with a kcat/Km of 7.5 × 107 M−1 min−1 but displays maximal activity against mixed-linkage polymeric xylans, hinting at a primary role in the degradation of marine polysaccharides. The three-dimensional structure of TtGH8 was solved in uncomplexed and xylobiose-, xylotriose- and xylohexaose-bound forms at approximately 1.5 Å resolution; the latter was consistent with the greater kcat/Km for hexasaccharide substrates. A 2,5B boat conformation observed in the −1 position of bound xylotriose is consistent with the proposed conformational itinerary for this class of enzyme. This work shows TtGH8 to be effective at the degradation of xylan-based substrates, notably marine xylan, further exemplifying the potential of T. turnerae for effective and diverse biomass degradation.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 Fowler et al. This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited. To view a copy of this license, visit https://creativecommons.org/licenses/by/2.0/uk/legalcode. |
Keywords: | glycoside hydrolase; biomass; biofuels; marine polysaccharides; cellulolytic enzymes; shipworms; Teredinibacter turnerae |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Molecular and Cellular Biology (Leeds) > Structural Molecular Biology (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 01 Nov 2018 10:41 |
Last Modified: | 01 Nov 2018 10:41 |
Status: | Published |
Publisher: | IUCr |
Identification Number: | 10.1107/S2059798318009737 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:137993 |