title: Mode of operation and low-resolution structure of a multi-domain and hyperthermophilic endo-β-1,3-glucanase from Thermotoga petrophila.
abstract: 1,3-β-Glucan depolymerizing enzymes have considerable biotechnological applications including biofuel production, feedstock-chemicals and pharmaceuticals. Here we describe a comprehensive functional characterization and low-resolution structure of a hyperthermophilic laminarinase from Thermotoga petrophila (TpLam). We determine TpLam enzymatic mode of operation, which specifically cleaves internal β-1,3-glucosidic bonds. The enzyme most frequently attacks the bond between the 3rd and 4th residue from the non-reducing end, producing glucose, laminaribiose and laminaritriose as major products. Far-UV circular dichroism demonstrates that TpLam is formed mainly by beta structural elements, and the secondary structure is maintained after incubation at 90°C. The structure resolved by small angle X-ray scattering, reveals a multi-domain structural architecture of a V-shape envelope with a catalytic domain flanked by two carbohydrate-binding modules.
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), do Centro Nacional de Pesquisa em Energia e Materiais, Campinas SP, Brazil.
authors.forename: Junio
authors.initials: J
authors.lastname: Cota
authors.forename: Thabata M
authors.initials: TM
authors.lastname: Alvarez
authors.forename: Ana P
authors.initials: AP
authors.lastname: Citadini
authors.forename: Camila Ramos
authors.initials: CR
authors.lastname: Santos
authors.forename: Mario
authors.initials: M
authors.lastname: de Oliveira Neto
authors.forename: Renata R
authors.initials: RR
authors.lastname: Oliveira
authors.forename: Glaucia M
authors.initials: GM
authors.lastname: Pastore
authors.forename: Roberto
authors.initials: R
authors.lastname: Ruller
authors.forename: Rolf A
authors.initials: RA
authors.lastname: Prade
authors.forename: Mario T
authors.initials: MT
authors.lastname: Murakami
authors.forename: Fabio M
authors.initials: FM
authors.lastname: Squina
mesh_terms: D044602:Cellulases; D004693:Glucan Endo-1,3-beta-D-Glucosidase / Q000737:chemistry* / Q000235:genetics; D006089:Gram-Negative Anaerobic Bacteria / Q000201:enzymology*; D006868:Hydrolysis; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D044602:Cellulases; D004693:Glucan Endo-1,3-beta-D-Glucosidase