title: Exogenous acetate ion reaches the type II copper centre in CueO through the water-excretion channel and potentially affects the enzymatic activity.
abstract: The acetate-bound form of the type II copper was found in the X-ray structure of the multicopper oxidase CueO crystallized in acetate buffer in addition to the conventional OH(-)-bound form as the major resting form. The acetate ion was retained bound to the type II copper even after prolonged exposure of a CueO crystal to X-ray radiation, which led to the stepwise reduction of the Cu centres. However, in this study, when CueO was crystallized in citrate buffer the OH(-)-bound form was present exclusively. This fact shows that an exogenous acetate ion reaches the type II Cu centre through the water channel constructed between domains 1 and 3 in the CueO molecule. It was also found that the enzymatic activity of CueO is enhanced in the presence of acetate ions in the solvent water.
authors.affiliation: Faculty of Education, Kagawa University, 1-1 Saiwai-cho, Takamatsu, Kagawa 760-8522, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Komori
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan.
authors.forename: Kunishige
authors.initials: K
authors.lastname: Kataoka
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan.
authors.forename: Sakiko
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan.
authors.forename: Nana
authors.initials: N
authors.lastname: Matsuda
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Higuchi
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sakurai
mesh_terms: D000085:Acetates / Q000737:chemistry*; D000838:Anions; D052160:Benzothiazoles / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry* / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000737:chemistry*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000085:Acetates; D000838:Anions; D052160:Benzothiazoles; D029968:Escherichia coli Proteins; D013451:Sulfonic Acids; D014867:Water; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D003300:Copper; D010088:Oxidoreductases
keywords: CueO; bioinorganic chemistry; enzyme catalysis; metalloproteins; multicopper oxidase