The xyl-doc gene cluster of Ruminiclostridium cellulolyticum encodes GH43- and GH62-α-l-arabinofuranosidases with complementary modes of action.

Détails

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Etat: Public
Version: Final published version
Licence: CC BY 4.0
ID Serval
serval:BIB_0A67B4908CA9
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
The xyl-doc gene cluster of Ruminiclostridium cellulolyticum encodes GH43- and GH62-α-l-arabinofuranosidases with complementary modes of action.
Périodique
Biotechnology for biofuels
Auteur(s)
Mroueh M., Aruanno M., Borne R., de Philip P., Fierobe H.P., Tardif C., Pagès S.
ISSN
1754-6834 (Print)
ISSN-L
1754-6834
Statut éditorial
Publié
Date de publication
2019
Peer-reviewed
Oui
Volume
12
Pages
144
Langue
anglais
Notes
Publication types: Journal Article
Publication Status: epublish
Résumé
The α-l-arabinofuranosidases (α-l-ABFs) are exoenzymes involved in the hydrolysis of α-l-arabinosyl linkages in plant cell wall polysaccharides. They play a crucial role in the degradation of arabinoxylan and arabinan and they are used in many biotechnological applications. Analysis of the genome of R. cellulolyticum showed that putative cellulosomal α-l-ABFs are exclusively encoded by the xyl-doc gene cluster, a large 32-kb gene cluster. Indeed, among the 14 Xyl-Doc enzymes encoded by this gene cluster, 6 are predicted to be α-l-ABFs belonging to the CAZyme families GH43 and GH62.
The biochemical characterization of these six Xyl-Doc enzymes revealed that four of them are α-l-ABFs. GH43 <sub>16</sub> -1229 (RcAbf43A) which belongs to the subfamily 16 of the GH43, encoded by the gene at locus Ccel_1229, has a low specific activity on natural substrates and can cleave off arabinose decorations located at arabinoxylan chain extremities. GH43 <sub>10</sub> -1233 (RcAbf43A <sub>d2,3</sub> ), the product of the gene at locus Ccel_1233, belonging to subfamily 10 of the GH43, can convert the double arabinose decorations present on arabinoxylan into single O2- or O3-linked decorations with high velocity (k <sub>cat</sub> = 16.6 ± 0.6 s <sup>-1</sup> ). This enzyme acts in synergy with GH62-1234 (RcAbf62A <sub>m2,3</sub> ), the product of the gene at locus Ccel_1234, a GH62 α-l-ABF which hydrolyzes α-(1 → 3) or α-(1 → 2)-arabinosyl linkages present on polysaccharides and arabinoxylooligosaccharides monodecorated. Finally, a bifunctional enzyme, GH62-CE6-1240 (RcAbf62B <sub>m2,3</sub> Axe6), encoded by the gene at locus Ccel_1240, which contains a GH62-α-l-ABF module and a carbohydrate esterase (CE6) module, catalyzes deacylation of plant cell wall polymers and cleavage of arabinosyl mono-substitutions. These enzymes are also active on arabinan, a component of the type I rhamnogalacturonan, showing their involvement in pectin degradation.
Arabinofuranosyl decorations on arabinoxylan and pectin strongly inhibit the action of xylan-degrading enzymes and pectinases. α-l-ABFs encoded by the xyl-doc gene cluster of R. cellulolyticum can remove all the decorations present in the backbone of arabinoxylan and arabinan, act synergistically, and, thus, play a crucial role in the degradation of plant cell wall polysaccharides.
Mots-clé
Arabinoxylan, Biomass degradation, Cellulosomes, Characterization of enzymes, Ruminiclostridium cellulolyticum, Substrate specificity, α-l-Arabinofuranosidase
Pubmed
Web of science
Open Access
Oui
Création de la notice
30/06/2019 16:17
Dernière modification de la notice
30/04/2021 7:08
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