title: Probing the Functions of Carbohydrate Binding Modules in the CBEL Protein from the Oomycete Phytophthora parasitica.
abstract: Oomycetes are microorganisms that are distantly related to true fungi and many members of this phylum are major plant pathogens. Oomycetes express proteins that are able to interact with plant cell wall polysaccharides, such as cellulose. This interaction is thought to be mediated by carbohydrate-binding modules that are classified into CBM family 1 in the CAZy database. In this study, the two CBMs (1-1 and 1-2) that form part of the cell wall glycoprotein, CBEL, from Phytophthora parasitica have been submitted to detailed characterization, first to better quantify their interaction with cellulose and second to determine whether these CBMs can be useful for biotechnological applications, such as biomass hydrolysis. A variety of biophysical techniques were used to study the interaction of the CBMs with various substrates and the data obtained indicate that CBEL's CBM1-1 exhibits much greater cellulose binding ability than CBM1-2. Engineering of the family 11 xylanase from Talaromyces versatilis (TvXynB), an enzyme that naturally bears a fungal family 1 CBM, has produced two variants. The first one lacks its native CBM, whereas the second contains the CBEL CBM1-1. The study of these enzymes has revealed that wild type TvXynB binds to cellulose, via its CBM1, and that the substitution of its CBM by oomycetal CBM1-1 does not affect its activity on wheat straw. However, intriguingly the addition of CBEL during the hydrolysis of wheat straw actually potentiates the action of TvXynB variant lacking a CBM1. This suggests that the potentiating effect of CBM1-1 might not require the formation of a covalent linkage to TvXynB.
authors.affiliation: Université Toulouse 3, UPS, Laboratoire de Recherche en Sciences Végétales, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France; CNRS, Laboratoire de Recherche en Sciences Végétales, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France; Université de Toulouse; INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France; CNRS, UMR5504, F-31400 Toulouse, France; INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400 Toulouse, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Martinez
authors.affiliation: Université de Toulouse; INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France; CNRS, UMR5504, F-31400 Toulouse, France; INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400 Toulouse, France; Cinabio ADISSEO France SAS, Hall Gilbert Durand 3, 135 avenue de Rangueil, 31077 Toulouse, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Texier
authors.affiliation: Université de Toulouse, UPS, IPBS, Toulouse, F-31077, France; Institut de Pharmacologie et de Biologie Structurale (IPBS), Centre National de la Recherche Scientifique (CNRS), Toulouse, F-31077, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Nahoum
authors.affiliation: Université Toulouse 3, UPS, Laboratoire de Recherche en Sciences Végétales, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France; CNRS, Laboratoire de Recherche en Sciences Végétales, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Lafitte
authors.affiliation: Université de Toulouse; INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France; CNRS, UMR5504, F-31400 Toulouse, France; INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400 Toulouse, France.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Cioci
authors.affiliation: CERMAV, CNRS, Grenoble, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Heux
authors.affiliation: Université Toulouse 3, UPS, Laboratoire de Recherche en Sciences Végétales, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France; CNRS, Laboratoire de Recherche en Sciences Végétales, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Dumas
authors.affiliation: Université de Toulouse; INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France; CNRS, UMR5504, F-31400 Toulouse, France; INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400 Toulouse, France.
authors.forename: Michael
authors.initials: M
authors.lastname: O'Donohue
authors.affiliation: Université Toulouse 3, UPS, Laboratoire de Recherche en Sciences Végétales, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France; CNRS, Laboratoire de Recherche en Sciences Végétales, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Gaulin
authors.affiliation: Université de Toulouse; INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France; CNRS, UMR5504, F-31400 Toulouse, France; INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400 Toulouse, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Dumon
mesh_terms: D001665:Binding Sites; D002482:Cellulose / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D037102:Lectins / Q000737:chemistry / Q000378:metabolism*; D010838:Phytophthora / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D032901:Talaromyces / Q000201:enzymology; D014908:Triticum / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D037102:Lectins; D002482:Cellulose; D043364:Endo-1,4-beta Xylanases