title: Identification and functional analysis of a gene encoding β-glucosidase from the brown-rot basidiomycete Fomitopsis palustris.
abstract: The brown-rot basidiomycete Fomitopsis palustris is known to degrade crystalline cellulose (Avicel) and produce three major cellulases, exoglucanases, endoglucanases, and β-glucosidases. A novel β-glucosidase designated as Cel3A was identified from F. palustris grown at the expense of Avicel. The deduced amino acid sequence of Cel3A showed high homology with those of other fungal β-glucosidases that belong to glycosyl hydrolase (GH) family 3. The sequence analysis also indicated that Cel3A contains the N- and C-terminal domains of GH family 3 and Asp-209 was conserved as a catalytic nucleophile. The cloned gene was successfully expressed in the yeast Pichia pastoris and the recombinant protein exhibited β-glucosidase activity with cellobiose and some degree of thermostability. Considering the size and sequence of the protein, the β-glucosidase identified in this study is different from the protein purified directly from F. palustris in the previous study. Our results suggest that the fungus possesses at least two β-glucosidase genes.
authors.affiliation: Microbial Biotechnology Lab, Department of Biotechnology (BK21-program), Chung-Ang University, Anseong, 456-756, Republic of Korea.
authors.forename: Hwang-Woo
authors.initials: HW
authors.lastname: Ji
authors.forename: Chang-Jun
authors.initials: CJ
authors.lastname: Cha
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002475:Cellobiose / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D003001:Cloning, Molecular; D055453:Coriolaceae / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D004795:Enzyme Stability; D005800:Genes, Fungal; D006358:Hot Temperature; D008969:Molecular Sequence Data; D010843:Pichia / Q000235:genetics; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D001617:beta-Glucosidase / Q000235:genetics*
chemical_list: D002475:Cellobiose; D002482:Cellulose; D001617:beta-Glucosidase