Assembly of preactivation complex for urease maturation in Helicobacter pylori: crystal structure of UreF-UreH protein complex

J Biol Chem. 2011 Dec 16;286(50):43241-9. doi: 10.1074/jbc.M111.296830. Epub 2011 Oct 19.

Abstract

Colonization of Helicobacter pylori in the acidic environment of the human stomach depends on the neutralizing activity of urease. Activation of apo-urease involves carboxylation of lysine 219 and insertion of two nickel ions. In H. pylori, this maturation process involves four urease accessory proteins as follows: UreE, UreF, UreG, and UreH. It is postulated that the apo-urease interacts with UreF, UreG, and UreH to form a pre-activation complex that undergoes GTP-dependent activation of urease. The crystal structure of the UreF-UreH complex reveals conformational changes in two distinct regions of UreF upon complex formation. First, the flexible C-terminal residues of UreF become ordered, forming an extra helix α10 and a loop structure stabilized by hydrogen bonds involving Arg-250. Second, the first turn of helix α2 uncoils to expose a conserved residue, Tyr-48. Substitution of R250A or Y48A in UreF abolishes the formation of the heterotrimeric complex of UreG-UreF-UreH and abolishes urease maturation. Our results suggest that the C-terminal residues and helix α2 of UreF are essential for the recruitment of UreG for the formation of the pre-activation complex. The molecular mass of the UreF-UreH complex determined by static light scattering was 116 ± 2.3 kDa, which is consistent with the quaternary structure of a dimer of heterodimers observed in the crystal structure. Taking advantage of the unique 2-fold symmetry observed in both the crystal structures of H. pylori urease and the UreF-UreH complex, we proposed a topology model of the pre-activation complex for urease maturation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Crystallography, X-Ray / methods*
  • Helicobacter pylori / genetics
  • Helicobacter pylori / metabolism*
  • Membrane Transport Proteins / chemistry
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism
  • Phosphate-Binding Proteins
  • Protein Binding
  • Protein Structure, Secondary
  • Urease / chemistry*
  • Urease / genetics
  • Urease / metabolism*

Substances

  • Bacterial Proteins
  • Carrier Proteins
  • Membrane Transport Proteins
  • Phosphate-Binding Proteins
  • UreF protein, bacteria
  • UreI protein, Helicobacter pylori
  • ureG protein, Bacteria
  • Urease

Associated data

  • PDB/3SF5