title: Functional Exploration of the Polysaccharide Lyase Family PL6.
abstract: Alginate, the main cell-wall polysaccharide of brown algae, is composed of two residues: mannuronic acid (M-residues) and, its C5-epimer, guluronic acid (G-residues). Alginate lyases define a class of enzymes that cleave the glycosidic bond of alginate by β-elimination. They are classified according to their ability to recognize the distribution of M- and G-residues and are named M-, G- or MG-lyases. In the CAZy database, alginate lyases have been grouped by sequence similarity into seven distinct polysaccharide lyase families. The polysaccharide lyase family PL6 is subdivided into three subfamilies. Subfamily PL6_1 includes three biochemically characterized enzymes (two alginate lyases and one dermatan sulfatase lyase). No characterized enzymes have been described in the two other subfamilies (PL6_2 and PL6_3). To improve the prediction of polysaccharide-lyase activity in the PL6 family, we re-examined the classification of the PL6 family and biochemically characterized a set of enzymes reflecting the diversity of the protein sequences. Our results show that subfamily PL6_1 includes two dermatan sulfates lyases and several alginate lyases that have various substrate specificities and modes of action. In contrast, subfamilies PL6_2 and PL6_3 were found to contain only endo-poly-MG-lyases.
authors.affiliation: CERMAV, CNRS and Grenoble Alpes Université, BP53, 38000, Grenoble, Cedex 9, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Mathieu
authors.affiliation: Centre National de la Recherche Scientifique (CNRS), UMR7257, Université Aix-Marseille, 13288, Marseille, France.|INRA, USC 1408 AFMB, 13288, Marseille, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Henrissat
authors.affiliation: CERMAV, CNRS and Grenoble Alpes Université, BP53, 38000, Grenoble, Cedex 9, France.
authors.forename: Flavien
authors.initials: F
authors.lastname: Labre
authors.affiliation: Department of Biotechnology, Norwegian University of Science and Technology, NTNU Sem Sælands vei 6-8, 7491, Trondheim, Norway.
authors.forename: Gudmund
authors.initials: G
authors.lastname: Skjåk-Bræk
authors.affiliation: CERMAV, CNRS and Grenoble Alpes Université, BP53, 38000, Grenoble, Cedex 9, France.
authors.forename: William
authors.initials: W
authors.lastname: Helbert
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000595:Amino Acid Sequence; D019295:Computational Biology; D018360:Crystallography, X-Ray; D030562:Databases, Protein; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics; D000459:Phaeophyceae / Q000201:enzymology; D010802:Phylogeny; D011133:Polysaccharide-Lyases / Q000737:chemistry / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D008565:Membrane Proteins; C526513:TMEM115 protein, human; C007896:guluronic acid; D020723:Glucuronic Acid; C008324:mannuronic acid; D011133:Polysaccharide-Lyases