title: The bioremediator glycerophosphodiesterase employs a non-processive mechanism for hydrolysis.
abstract: Glycerophosphodiesterase (GpdQ) from Enterobacter aerogenes is a binuclear metallohydrolase that catalyzes the breakdown of a broad range of phosphate ester substrates, and it is of interest for its potential application in the destruction of organophosphate nerve agents and pesticides. The reaction mechanism of GpdQ has been proposed to involve a nucleophilic attack by a terminally bound hydroxide molecule. The hydroxide species bridging the two metal ions is suggested to activate the nucleophile, thus favoring a sequential rather than a processive mechanism of action. Here, the hydrolysis of the two ester bonds in the substrate bis(para-nitrophenyl) phosphate (bpNPP) is probed using (31)P NMR. The kinetic rates measured compare well with those determined spectrophotometrically. Furthermore, the data indicate that the diester bonds are cleaved in two separate (non-processive) reactions, indicating that only a single nucleophile (the terminal hydroxide molecule) is likely to be employed as a nucleophile for GpdQ.
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
authors.forename: Kieran S
authors.initials: KS
authors.lastname: Hadler
authors.forename: Lawrence R
authors.initials: LR
authors.lastname: Gahan
authors.forename: David L
authors.initials: DL
authors.lastname: Ollis
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schenk
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D055162:Biocatalysis; D020134:Catalytic Domain; D021902:Enterobacter aerogenes / Q000201:enzymology*; D006868:Hydrolysis; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D015394:Molecular Structure; D009596:Nitrophenols / Q000737:chemistry / Q000378:metabolism; D010755:Organophosphates / Q000737:chemistry / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000737:chemistry / Q000378:metabolism; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry* / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D009596:Nitrophenols; D010755:Organophosphates; D009943:Organophosphorus Compounds; C008644:nitrophenylphosphate; D010727:Phosphoric Diester Hydrolases; C038133:glycerophosphodiester phosphodiesterase