Toggle Main Menu Toggle Search

Open Access padlockePrints

Structural insight into the ligand specificity of a thermostable family 51 arabinofuranosidase, Araf51, from Clostridium thermocellum

Lookup NU author(s): Dr Edward Taylor, Emeritus Professor Harry Gilbert


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


The digestion of the plant cell wall requires the concerted action of a diverse repertoire of enzyme activities. An important component of these hydrolase consortia are arabinofuranosidases, which release L-arabinofuranose moieties from a range of plant structural polysaccharides. The anaerobic bacterium Clostridium thermocellum, a highly efficient plant cell wall degrader, possesses a single α-L-arabinofuranosidase (EC, CtAraf51A, located in GH51 (glycoside hydrolase family 51). The crystal structure of the enzyme has been solved in native form and in 'Michaelis' complexes with both α-1,5-linked arabinotriose and α-1,3 arabinoxylobiose, both forming a hexamer in the asymmetric unit. Kinetic studies reveal that CtAraf51A, in contrast with well-characterized GH51 enzymes including the Cellvibrio japonicus enzyme [Beylot, McKie, Voragen, Doeswijk-Voragen and Gilbert (2001) Biochem. J. 358, 607-614], catalyses the hydrolysis of α-1,5-linked arabino-oligosaccharides and the α-1,3 arabinosyl side chain decorations of xylan with equal efficiency. The paucity of direct hydrogen bonds with the aglycone moiety and the flexible conformation adopted by Trp178, which stacks against the sugar at the +1 subsite, provide a structural explanation for the plasticity in substrate specificity displayed by the clostridial arabinofuranosidase. © 2006 Biochemical Society.

Publication metadata

Author(s): Taylor EJ, Smith NL, Turkenburg JP, D'Souza S, Gilbert HJ, Davies GJ

Publication type: Article

Publication status: Published

Journal: Biochemical Journal

Year: 2006

Volume: 395

Issue: 1

Pages: 31-37

ISSN (print): 0264-6021

ISSN (electronic): 1470-8728

Publisher: Portland Press Ltd.


DOI: 10.1042/BJ20051780

PubMed id: 16336192


Altmetrics provided by Altmetric