Fluoride Inhibition of Sporosarcina Pasteurii Urease: Structure and Thermodynamics.
Benini, S., Cianci, M., Mazzei, L., Ciurli, S.(2014) J.Biol.Inorg.Chem. 19: 1243
- PubMed: 25113581 Search on PubMed
- DOI: 10.1007/s00775-014-1182-x
- Primary Citation of Related Structures:  
- PubMed Abstract: 
- Molecular Details of Urease Inhibition by Boric Acid: Insights Into the Catalytic Mechanism.
Benini, S.,Rypniewski, W.R.,Wilson, K.S.,Mangani, S.,Ciurli, S.
(2004) J.Am.Chem.Soc. 126: 3714 - The Complex of Bacillus Pasteurii Urease with Acetohydroxamate Anion from X-Ray Data at 1.55 A Resolution.
Benini, S.,Rypniewski, W.R.,Wilson, K.S.,Miletti, S.,Ciurli, S.,Mangani, S.
(2000) J.Biol.Inorg.Chem. 5: 110 - A New Proposal for Urease Mechanism Based on the Crystal Structures of the Native and Inhibited Enzyme from Bacillus Pasteurii: Why Urea Hydrolysis Costs Two Nickels.
Benini, S.,Rypniewski, W.R.,Wilson, K.S.,Miletti, S.,Ciurli, S.,Mangani, S.
(1999) Structure 7: 205 - The Complex of Bacillus Pasteurii Urease with Beta-Mercaptoethanol from X-Ray Data at 1.65 A Resolution
Benini, S.,Ciurli, S.,Rypniewski, W.R.,Wilson, K.S.,Mangani, S.
(1998) J.Biol.Inorg.Chem. 3: 268 - Structure-Based Rationalization of Urease Inhibition by Phosphate: Novel Insights Into the Enzyme Mechanism.
Benini, S.,Rypniewski, W.R.,Wilson, K.S.,Ciurli, S.,Mangani, S.
(2001) J.Biol.Inorg.Chem. 6: 778 - The Crystal Structure of Sporosarcina Pasteurii Urease in a Complex with Citrate Provides New Hints for Inhibitor Design.
Benini, S.,Kosikowska, P.,Cianci, M.,Mazzei, L.,Vara, A.G.,Berlicki, L.,Ciurli, S.
(2013) J.Biol.Inorg.Chem. 18: 391 - Crystallization and Preliminary High-Resolution X-Ray Diffraction Analysis of Native and Beta-Mercaptoethanol-Inhibited Urease from Bacillus Pasteurii.
Benini, S.,Ciurli, S.,Rypniewski, W.R.,Wilson, K.S.,Mangani, S.
(1998) Acta Crystallogr.,Sect.D 54: 409
Urease is a nickel-dependent enzyme and a virulence factor for ureolytic bacterial human pathogens, but it is also necessary to convert urea, the most worldwide used fertilizer, into forms of nitrogen that can be taken up by crop plants. A strategy t ...
Urease is a nickel-dependent enzyme and a virulence factor for ureolytic bacterial human pathogens, but it is also necessary to convert urea, the most worldwide used fertilizer, into forms of nitrogen that can be taken up by crop plants. A strategy to control the activity of urease for medical and agricultural applications is to use enzyme inhibitors. Fluoride is a known urease inhibitor, but the structural basis of its mode of inhibition is still undetermined. Here, kinetic studies on the fluoride-induced inhibition of urease from Sporosarcina pasteurii, a widespread and highly ureolytic soil bacterium, were performed using isothermal titration calorimetry and revealed a mixed competitive and uncompetitive mechanism. The pH dependence of the inhibition constants, investigated in the 6.5-8.0 range, reveals a predominant uncompetitive mechanism that increases by increasing the pH, and a lesser competitive inhibition that increases by lowering the pH. Ten crystal structures of the enzyme were independently determined using five crystals of the native form and five crystals of the protein crystallized in the presence of fluoride. The analysis of these structures revealed the presence of two fluoride anions coordinated to the Ni(II) ions in the active site, in terminal and bridging positions. The present study consistently supports an interaction of fluoride with the nickel centers in the urease active site in which one fluoride competitively binds to the Ni(II) ion proposed to coordinate urea in the initial step of the catalytic mechanism, while another fluoride uncompetitively substitutes the Ni(II)-bridging hydroxide, blocking its nucleophilic attack on urea.
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Organizational Affiliation: 
Faculty of Science and Technology, Free University of Bolzano, Piazza Università 5, 39100, Bolzano, Italy, stefano.benini@unibz.it.