title: TPR domain of Ser/Thr phosphatase of Aspergillus oryzae shows no auto-inhibitory effect on the dephosphorylation activity.
abstract: A Ser/Thr phosphatase gene cloned from Aspergillus oryzae, aoppt, revealed that the tetratricopeptide repeat (TPR) and catalytic domains of the full-length AoPPT are located at the N- and C-terminal regions, respectively, similar to those of human Ser/Thr phosphatase 5 (PP5) and yeast Ppt1. Four different regions of AoPPT, namely, a full-length polypeptide, the catalytic domain, the catalytic domain plus C-terminal 15 amino-acid residues and the TPR domain were expressed in Escherichia coli and their roles in dephosphorylation activity were examined, using p-nitrophenyl phosphate as the substrate. The full-length AoPPT showed the highest dephosphorylation activity while the catalytic domain had the lowest activity. The activity of the catalytic domain was not inhibited by the presence of the TPR domain and arachidonic acid did not increase the activity of the full-length enzyme. These findings suggest that the integrity of the entire enzyme would be necessary for its full activity to be expressed.
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, 3-1-1, Tsushima-Naka, Okayama 700-8530, Japan.
authors.forename: Bin
authors.initials: B
authors.lastname: Feng
authors.forename: Chun-Hui
authors.initials: CH
authors.lastname: Zhao
authors.forename: Soukichi
authors.initials: S
authors.lastname: Tanaka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Imanaka
authors.forename: Koreyoshi
authors.initials: K
authors.lastname: Imamura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nakanishi
mesh_terms: D001236:Aspergillus oryzae / Q000201:enzymology* / Q000235:genetics; D020134:Catalytic Domain / Q000235:genetics; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics; D009596:Nitrophenols / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*; D010749:Phosphoprotein Phosphatases / Q000737:chemistry* / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D005656:Fungal Proteins; D009596:Nitrophenols; D009943:Organophosphorus Compounds; C008644:nitrophenylphosphate; D010749:Phosphoprotein Phosphatases