title: Domain structure and function of α-1,3-glucanase from Bacillus circulans KA-304, an enzyme essential for degrading basidiomycete cell walls.
abstract: Bacillus circulans KA-304 α-1,3-glucanase (Agl-KA) includes an N-terminal discoidin domain (DS1), a carbohydrate binding module family 6 (CB6), threonine and proline repeats (TPs), a second discoidin domain (DS2), an uncharacterized conserved domain (UCD), and a C-terminal catalytic domain. Domain deletion enzymes lacking DS1, CB6, and DS2 exhibited lower α-1,3-glucan-hydrolyzing and -binding activities than the wild type, Agl-KA. An α-1,3-glucan binding assay with fluorescent protein fusion proteins indicated that DS1, CB6, and DS2 bound to α-1,3-glucan and fungal cell walls, and that binding efficiency was increased by their combined action. In contrast, UCD did not exhibit any α-1,3-glucan-binding activity. A dramatic decrease in protoplast formation in the Schizophyllum commune mycelium was observed given only a DS1 deletion. An Agl-KA with deletion DS1, CB6, and DS2 produced no protoplasts. These results indicate that the combined actions of DS1, CB6, and DS2 contributed to increased cell-wall binding and were indispensable for efficient Agl-KA cell-wall degradation.
authors.affiliation: Department of Biotechnology, Faculty of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan.
authors.forename: Wasana
authors.initials: W
authors.lastname: Suyotha
authors.forename: Shigekazu
authors.initials: S
authors.lastname: Yano
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Takagi
authors.forename: Nopakarn
authors.initials: N
authors.lastname: Rattanakit-Chandet
authors.forename: Takashi
authors.initials: T
authors.lastname: Tachiki
authors.forename: Mamoru
authors.initials: M
authors.lastname: Wakayama
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D002473:Cell Wall / Q000378:metabolism*; D005936:Glucans / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006868:Hydrolysis; D017434:Protein Structure, Tertiary; D011523:Protoplasts / Q000378:metabolism; D012567:Schizophyllum / Q000166:cytology*; D017384:Sequence Deletion
chemical_list: D005936:Glucans; C045788:alpha-1,3-glucan; D006026:Glycoside Hydrolases; C021780:exo-1,3-alpha-glucanase