The survival and growth of the pathogen Helicobacter pylori in the gastric acidic environment is ensured by the activity of urease, an enzyme containing two essential Ni2+ ions in the active site. The metallo-chaperone UreE facilitates in vivo Ni2+ insertion into the apoenzyme. Crystals of apo-HpUreE (H. pylori UreE) and its Ni2+- and Zn2+-bound forms were obtained from protein solutions in the absence and presence of the metal ions. The crystal structures of the homodimeric protein, determined at 2.00 Å (apo), 1.59 Å (Ni2+) and 2.52 Å (Zn2+) resolution, show the conserved proximal and solvent-exposed His102 residues from two adjacent monomers invariably involved in metal binding. The C-terminal regions of the apoprotein are disordered in the crystal, but acquire significant ordering in the presence of the metal ions due to the binding of His152. The analysis of X-ray absorption spectral data obtained using solutions of Ni2+- and Zn2+-bound HpUreE provided accurate information of the metal-ion environment in the absence of solid-state effects. These results reveal the role of the histidine residues at the protein C-terminus in metal-ion binding, and the mutual influence of protein framework and metal-ion stereo-electronic properties in establishing co-ordination number and geometry leading to metal selectivity.
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Research Article|
January 16 2012
Crystallographic and X-ray absorption spectroscopic characterization of Helicobacter pylori UreE bound to Ni2+ and Zn2+ reveals a role for the disordered C-terminal arm in metal trafficking
Katarzyna Banaszak;
Katarzyna Banaszak
1
*Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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Vlad Martin-Diaconescu;
Vlad Martin-Diaconescu
1
†Department of Chemistry, University of Massachusetts, Amherst, MA 01003, U.S.A.
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Matteo Bellucci;
Matteo Bellucci
‡Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
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Barbara Zambelli;
Barbara Zambelli
‡Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
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Wojciech Rypniewski;
Wojciech Rypniewski
*Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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Michael J. Maroney;
Michael J. Maroney
†Department of Chemistry, University of Massachusetts, Amherst, MA 01003, U.S.A.
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Stefano Ciurli
Stefano Ciurli
2
‡Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
§Center for Magnetic Resonance (CERM), University of Florence, Via Luigi Sacconi 6, I-50019 Sesto Fiorentino, Italy
2To whom correspondence should be addressed (email stefano.ciurli@unibo.it).
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Publisher: Portland Press Ltd
Received:
September 13 2011
Revision Received:
October 20 2011
Accepted:
October 20 2011
Accepted Manuscript online:
October 20 2011
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© The Authors Journal compilation © 2012 Biochemical Society
2012
Biochem J (2012) 441 (3): 1017–1035.
Article history
Received:
September 13 2011
Revision Received:
October 20 2011
Accepted:
October 20 2011
Accepted Manuscript online:
October 20 2011
Citation
Katarzyna Banaszak, Vlad Martin-Diaconescu, Matteo Bellucci, Barbara Zambelli, Wojciech Rypniewski, Michael J. Maroney, Stefano Ciurli; Crystallographic and X-ray absorption spectroscopic characterization of Helicobacter pylori UreE bound to Ni2+ and Zn2+ reveals a role for the disordered C-terminal arm in metal trafficking. Biochem J 1 February 2012; 441 (3): 1017–1035. doi: https://doi.org/10.1042/BJ20111659
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