Binding of bismuth (III) to UreG disrupts urease maturation.

<p>(A) Analysis of Bi-binding proteins in live <i>H</i>. <i>pylori</i> cells by 2-DE. The proteins that bind to Bi(III) are highlighted in blue squares on the SDS-PAGE (as UreA, UreB and UreG), while those that do not bind Bi(III) are in orange squares (as UreF, UreH). (B) UV-vis spectra of UreG in HEPES buffer titrated with BiNTA with the titration curve shown in the inset. (C) Gel filtration profiles of protein complexes with or without Bi(III). In the presence of Mg(II) and GTP (without Ni(II)), 2G-2F-2H complex was eluted at approximately 10.5 ml. Incubation with two molar equivalents of Bi(III) resulted in the dissociation of UreG from 2F-2H complex. An excess amount of UreG was used and eluted as a monomer at approximately 14 ml (green curve). (D) Activity of UreG as a GTPase. The activity of apo- or Ni-bound UreG was examined, whereas the Ni-UreG was incubated with varying concentrations of Bi(III) ions to study the effects of Bi(III) ions on UreG activity. (E) Analysis of the effects of metal–UreG interaction on the urease activity. Apo- or metal-treated UreG was supplemented to the cell lysate of <i>Escherichia coli</i>-expressing urease gene cluster, excluding <i>ureG</i> gene, prior to analysis (incubation for 40 min). The activities of UreG or urease in the samples without CBS treatment were set as 100%; the activities of the negative control (without addition of UreG into the reactions) were set as 0. The underlying data for Fig 1D and 1E can be found in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2003887#pbio.2003887.s001" target="_blank">S1 Data</a>. 2-DE, 2-dimensional gel electrophoresis; CBS, colloidal bismuth subcitrate.