title: The N-terminal family 22 carbohydrate-binding module of xylanase 10B of Clostridium themocellum is not a thermostabilizing domain.
abstract: Xylanase Xyn10B from Clostridium thermocellum is a modular enzyme that contains two family 22 carbohydrate binding modules N- (CBM22-1) and C- (CBM22-2) terminal of the family 10 glycoside hydrolase catalytic domain (GH10). In a previous study, we showed that removal of CBM22-1 reduces the resistance to thermoinactivation of the enzyme suggesting that this module is a thermostabilizing domain. Here, we show that it is the module border on the N-terminal side of GH10 that confers resistance to thermoinactivation and to proteolysis. Therefore, CBM22-1 does not function as a thermostabilizing domain and the role for this apparently non-functional CBM remains elusive.
authors.affiliation: Universidade Técnica de Lisboa, CIISA--Faculdade de Medicina Veterinária, Rua Prof. Cid dos Santos, 1300-477 Lisboa, Portugal.
authors.forename: Fernando M V
authors.initials: FM
authors.lastname: Dias
authors.forename: Arun
authors.initials: A
authors.lastname: Goyal
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Gilbert
authors.lastname: José A M  Prates
authors.forename: Luís M A
authors.initials: LM
authors.lastname: Ferreira
authors.forename: Carlos M G A
authors.initials: CM
authors.lastname: Fontes
mesh_terms: D001665:Binding Sites; D020134:Catalytic Domain; D003013:Clostridium / Q000201:enzymology*; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004795:Enzyme Stability; D006358:Hot Temperature; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010447:Peptide Hydrolases / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D017434:Protein Structure, Tertiary; D017384:Sequence Deletion; D012995:Solubility; D014990:Xylans / Q000378:metabolism
chemical_list: D011134:Polysaccharides; D014990:Xylans; D043364:Endo-1,4-beta Xylanases; D010447:Peptide Hydrolases