title: A novel thermophilic endo-β-1,4-mannanase from Aspergillus nidulans XZ3: functional roles of carbohydrate-binding module and Thr/Ser-rich linker region.
abstract: The gene man5XZ3 from Aspergillus nidulans XZ3 encodes a multimodular β-mannanase of glycoside hydrolase family 5 that consists of a family 1 carbohydrate-binding module (CBM1), a Thr/Ser-rich linker region, and a catalytic domain. Recombinant Man5XZ3 and its two truncated derivatives, Man5ΔCBM (removing the CBM1) and Man5ΔCL (removing both the CBM1 and linker region), were produced in Pichia pastoris and showed significant variance in the secondary structure. The three enzymes had similar biochemical properties, such as optimal pH and temperature (pH 5.0 and 80 °C) and excellent pH stability at pH 4.0-10.0. Removal of the CBM1 alone could improve the thermostability of Man5XZ3, but further removal of the linker region resulted in worse thermostability. Man5XZ3 retained greater enzyme activity in the presence of an organic solvent (acetone), two detergents (SDS and Triton X-100), and a chaotropic agent (urea) compared with Man5ΔCBM and Man5ΔCL. This study provides an excellent β-mannanase candidate favorable for various industries and primarily demonstrates the relationship between enzyme structure and function.
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: Huiying
authors.initials: H
authors.lastname: Luo
authors.forename: Pengjun
authors.initials: P
authors.lastname: Shi
authors.forename: Huoqing
authors.initials: H
authors.lastname: Huang
authors.forename: Kun
authors.initials: K
authors.lastname: Meng
authors.forename: Peilong
authors.initials: P
authors.lastname: Yang
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics; D001665:Binding Sites; D004252:DNA Mutational Analysis; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D008361:Mannosidases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010843:Pichia / Q000235:genetics; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017384:Sequence Deletion; D013696:Temperature
chemical_list: D011994:Recombinant Proteins; D008361:Mannosidases; C041867:endo-1,4-beta-D-mannanase