Crystal Structure of Klebsiella Aerogenes Uree, a Nickel-Binding Metallochaperone for Urease Activation
Song, H.K., Mulrooney, S.B., Huber, R., Hausinger, R.(2001) J Biol Chem 276: 49359
- PubMed: 11591723 
- DOI: https://doi.org/10.1074/jbc.M108619200
- Primary Citation of Related Structures:  
1GMU, 1GMV, 1GMW - PubMed Abstract: 
UreE is proposed to be a metallochaperone that delivers nickel ions to urease during activation of this bacterial virulence factor. Wild-type Klebsiella aerogenes UreE binds approximately six nickel ions per homodimer, whereas H144*UreE (a functional C-terminal truncated variant) was previously reported to bind two. We determined the structure of H144*UreE by multi-wavelength anomalous diffraction and refined it to 1.5 A resolution. The present structure reveals an Hsp40-like peptide-binding domain, an Atx1-like metal-binding domain, and a flexible C terminus. Three metal-binding sites per dimer, defined by structural analysis of Cu-H144*UreE, are on the opposite face of the Atx1-like domain than observed in the copper metallochaperone. One metal bridges the two subunits via the pair of His-96 residues, whereas the other two sites involve metal coordination by His-110 and His-112 within each subunit. In contrast to the copper metallochaperone mechanism involving thiol ligand exchanges between structurally similar chaperones and target proteins, we propose that the Hsp40-like module interacts with urease apoprotein and/or other urease accessory proteins, while the Atx1-like domain delivers histidyl-bound nickel to the urease active site.
Organizational Affiliation: 
Abteilung Strukturforschung, Max-Planck-Institut für Biochemie, Am Klopferspitz 18a, D-82152, Planegg-Martinsried, Germany. hksong@red.dfci.harvard.edu