title: Crystal structure of an acetylesterase from Talaromyces cellulolyticus and the importance of a disulfide bond near the active site.
abstract: Carbohydrate esterase catalyzes the de-O or de-N-acylation of substituted saccharides in plant cell walls and thus has great potential for industrial biomass saccharification. We recently identified the putative carbohydrate esterase family 3 (CE3) from Talaromyces cellulolyticus. Here, we prepared the recombinant catalytic domain of the enzyme and crystallized it. The crystal structure was determined to 1.5 Å resolution. From the structural analysis, it was elucidated that a n-octyl-β-D-glucopyranoside bound to near the catalytic triad (Ser10, Asp179 and His182) and was buried in the active site cavity. Site-directed mutagenesis showed that the N-terminal disulfide bond located near the catalytic triad is involved in the activity and structural stability of the enzyme.
authors.affiliation: Biomass Refinery Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Fukada
authors.affiliation: Biomass Refinery Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
authors.affiliation: Biomass Refinery Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046, Japan. Electronic address: kazu-ishikawa@aist.go.jp.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishikawa
mesh_terms: D000115:Acetylesterase / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D013329:Structure-Activity Relationship; D032901:Talaromyces / Q000201:enzymology* / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D011994:Recombinant Proteins; D000115:Acetylesterase
keywords: Biomass; Carbohydrate esterase; Catalytic triad; Disulfide bond; Saccharification; Xylanase