Structural Basis for Ni2+ Transport and Assembly of the Urease Active Site by the Metallochaperone UreE from Bacillus pasteurii

ArticleinJournal of Biological Chemistry 276(52):49365-70 · January 2002with3 Reads
Impact Factor: 4.57 · DOI: 10.1074/jbc.M108304200 · Source: PubMed

    Abstract

    Bacillus pasteurii UreE (BpUreE) is a putative chaperone assisting the insertion of Ni2+ ions in the active site of urease. The x-ray structure of the protein has been determined for two crystal forms, at 1.7 and
    1.85 Å resolution, using SIRAS phases derived from a Hg2+-derivative. BpUreE is composed of distinct N- and C-terminal domains, connected by a short flexible linker. The structure reveals the topology
    of an elongated homodimer, formed by interaction of the two C-terminal domains through hydrophobic interactions. A single
    Zn2+ ion bound to four conserved His-100 residues, one from each monomer, connects two dimers resulting in a tetrameric BpUreE known to be formed in concentrated solutions. The Zn2+ ion can be replaced by Ni2+as shown by anomalous difference maps obtained on a crystal ofBpUreE soaked in a solution containing NiCl2. A large hydrophobic patch surrounding the metal ion site is surface-exposed in the biologically relevant dimer. TheBpUreE structure represents the first for this class of proteins and suggests a possible role for UreE in the urease nickel-center
    assembly.