title: Phosphate-bound structure of an organophosphate-degrading enzyme from Agrobacterium radiobacter.
abstract: OpdA is a binuclear metalloenzyme that can hydrolyze organophosphate pesticides and nerve agents. In this study the crystal structure of the complex between OpdA and phosphate has been determined to 2.20 Å resolution. The structure shows the phosphate bound in a tripodal mode to the metal ions whereby two of the oxygen atoms of PO(4) are terminally bound to each metal ion and a third oxygen bridges the two metal ions, thus displacing the μOH in the active site. In silico modelling demonstrates that the phosphate moiety of a reaction product, e.g. diethyl phosphate, may bind in the same orientation, positioning the diethyl groups neatly into the substrate binding pocket close to the metal center. Thus, similar to the binuclear metallohydrolases urease and purple acid phosphatase the tripodal arrangement of PO(4) is interpreted in terms of a role of the μOH as a reaction nucleophile.
authors: School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia.
authors: Fernanda
authors: F
authors: Ely
authors: Marcelo M
authors: MM
authors: Pedroso
authors: Lawrence R
authors: LR
authors: Gahan
authors: David L
authors: DL
authors: Ollis
authors: Luke W
authors: LW
authors: Guddat
authors: Gerhard
authors: G
authors: Schenk
mesh_terms: D000135:Acid Phosphatase / Q000737:chemistry / Q000378:metabolism; D016960:Agrobacterium tumefaciens / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D055162:Biocatalysis; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D006867:Hydrolases / Q000737:chemistry / Q000378:metabolism; D006868:Hydrolysis; D007700:Kinetics; D008667:Metalloproteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D010755:Organophosphates / Q000378:metabolism*; D044345:Phosphoric Triester Hydrolases / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D008667:Metalloproteins; D010755:Organophosphates; D006867:Hydrolases; D000135:Acid Phosphatase; D044345:Phosphoric Triester Hydrolases