title: Expression and Characterization of a Novel Antifungal Exo-β-1,3-glucanase from Chaetomium cupreum.
abstract: A novel β-1,3-glucanase gene, designated Ccglu17A, was cloned from the biological control fungus Chaetomium cupreum Ame. Its 1626-bp open reading frame encoded 541 amino acids. The corresponding amino acid sequence showed highest identity (67 %) with a glycoside hydrolase family 17 β-1,3-glucanase from Chaetomium globosum. The recombinant protein Ccglu17A was successfully expressed in Pichia pastoris, and the enzyme was purified to homogeneity with 10.1-fold purification and 47.8 % recovery yield. The protein's molecular mass was approximately 65 kDa, and its maximum activity appeared at pH 5.0 and temperature 45 °C. Heavy metal ions Fe2+, Mn2+, Cu2+, Co2+, Ag+, and Hg2+had inhibitory effects on Ccglu17A, but Ba2+promoted the enzyme's activity. Ccglu17A exhibited high substrate specificity, almost exclusively catalyzing β-1,3-glycosidic bond cleavage in various polysaccharoses to liberate glucose. The enzyme had a Km of 2.84 mg/mL and Vmax of 10.7 μmol glucose/min/mg protein for laminarin degradation under optimal conditions. Ccglu17A was an exoglucanase with transglycosylation activity based on its hydrolytic properties. It showed potential antifungal activity with a degradative effect on cell walls and inhibitory action against the germination of pathogenic fungus. In conclusion, Ccglu17A is the first functional exo-1,3-β-glucanase to be identified from C. cupreum and has potential applicability in industry and agriculture.
authors.affiliation: School of Life Science and Technology, Harbin Institute of Technology, Nangang District, Harbin, People's Republic of China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Jiang
authors.affiliation: School of Life Science and Technology, Harbin Institute of Technology, Nangang District, Harbin, People's Republic of China.
authors.forename: Jinzhu
authors.initials: J
authors.lastname: Song
authors.affiliation: School of Life Science and Technology, Harbin Institute of Technology, Nangang District, Harbin, People's Republic of China.
authors.forename: Hua
authors.initials: H
authors.lastname: Cong
authors.affiliation: School of Chemical Engineering and Technology, Harbin Institute of Technology, Nangang District, Harbin, People's Republic of China. hitzjz@hit.edu.cn.
authors.forename: Junzheng
authors.initials: J
authors.lastname: Zhang
authors.affiliation: School of Life Science and Technology, Harbin Institute of Technology, Nangang District, Harbin, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yang
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D002413:Cations, Divalent; D002597:Chaetomium / Q000737:chemistry / Q000145:classification / Q000201:enzymology*; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D005670:Fusarium / Q000187:drug effects / Q000254:growth & development; D015870:Gene Expression; D043326:Glucan 1,3-beta-Glucosidase / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D005936:Glucans / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D019216:Metals, Heavy / Q000737:chemistry; D008970:Molecular Weight; D016366:Open Reading Frames; D010802:Phylogeny; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development; D013379:Substrate Specificity
chemical_list: D000935:Antifungal Agents; D002413:Cations, Divalent; D005656:Fungal Proteins; D005936:Glucans; D019216:Metals, Heavy; D011994:Recombinant Proteins; C008247:laminaran; D043326:Glucan 1,3-beta-Glucosidase
keywords: Antifungal; Chaetomium cupreum; Exo-β-1,3-glucanase; Hydrolysis; Laminarin