title: A family 5 β-mannanase from the thermophilic fungus Thielavia arenaria XZ7 with typical thermophilic enzyme features.
abstract: A novel β-mannanase gene, man5XZ7, was cloned from thermophilic fungus Thielavia arenaria XZ7, and successfully expressed in Pichia pastoris. The gene (1,110 bp) encodes a 369-amino acid polypeptide with a molecular mass of approximately 40.8 kDa. The deduced sequence of Man5XZ7 consists of a putative 17-residue signal peptide and a catalytic module belonging to glycoside hydrolase (GH) family 5, and displays 76 % identity with the experimentally verified GH 5 endo-β-1,4-mannanase from Podospora anserina. Recombinant Man5XZ7 was optimally active at 75 °C and pH 5.0 and exhibited high activity at a wide temperature range (>50.0 % activity at 50-85 °C). Moreover, it had good adaptability to acidic to basic pH (>74.1 % activity at pH 4.0-7.0 and 25.6 % even at pH 9.0) and good stability from pH 3.0 to 10.0. These enzymatic properties showed that Man5XZ7 was a new thermophilic and alkali-tolerant β-mannanase. Further amino acid composition analysis indicated that Man5XZ7 has several characteristic features of thermophilic enzymes.
authors.affiliation: Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No.12 Zhongguancun South Street, Beijing, 100081, People's Republic of China.
authors.forename: Haiqiang
authors.initials: H
authors.lastname: Lu
authors.forename: Huitu
authors.initials: H
authors.lastname: Zhang
authors.forename: Pengjun
authors.initials: P
authors.lastname: Shi
authors.forename: Huiying
authors.initials: H
authors.lastname: Luo
authors.forename: Yaru
authors.initials: Y
authors.lastname: Wang
authors.forename: Peilong
authors.initials: P
authors.lastname: Yang
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight; D005810:Multigene Family; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D020037:Sordariales / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D044902:beta-Mannosidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D021382:Protein Sorting Signals; D044902:beta-Mannosidase