title: Engineering the thermostability of a xylanase from Aspergillus oryzae by an enhancement of the interactions between the N-terminus extension and the β-sheet A2 of the enzyme.
abstract: A mesophilic Aspergillus oryzae xylanase (AoXyn11A) belongs to glycoside hydrolase family 11. Hydrogen bonds and a disulfide bridge were introduced between the N-terminus extension and the β-sheet A2 of AoXyn11A, which were located in the corresponding region of a hyperthermostable xylanase. The mutants were designated as AoXyn11A(C5) and AoXyn11A(C5-C32), respectively. The thermostabilities of AoXyn11A and the mutants were assessed by the molecular dynamics simulations. After being incubated at 55 °C for 30 min, AoXyn11A(C5-C32) retained 49 % of its original activity, AoXyn11A(C5) retained 12 % and AoXyn11A retained 3 %. The interactions between the N-terminus extension and the β-sheet A2 were analyzed in depth: there was enhancement of the interactions between the N-terminus extension and the β-sheet A2 of AoXyn11A that improved its thermostability.
authors.affiliation: School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, People's Republic of China.
authors.forename: Zhongfa
authors.initials: Z
authors.lastname: Chen
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhang
authors.forename: Junqing
authors.initials: J
authors.lastname: Wang
authors.forename: Cunduo
authors.initials: C
authors.lastname: Tang
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.forename: Minchen
authors.initials: M
authors.lastname: Wu
mesh_terms: D000595:Amino Acid Sequence; D001236:Aspergillus oryzae / Q000201:enzymology* / Q000235:genetics; D004220:Disulfides; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015202:Protein Engineering / Q000379:methods*; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D004220:Disulfides; D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D043364:Endo-1,4-beta Xylanases