• DOI:10.1038/88563
• Corpus ID: 26548257

Supramolecular assembly and acid resistance of Helicobacter pylori urease

@article{Ha2001SupramolecularAA,
  title={Supramolecular assembly and acid resistance of Helicobacter pylori urease},
  author={Nam-Chul Ha and Sang-Taek Oh and Jae Young Sung and Kyeung Ah Cha and Mann-Hyung Lee and Byung-Ha Oh},
  journal={Nature Structural Biology},
  year={2001},
  volume={8},
  pages={505-509}
}

• N. Ha, Sang-Taek Oh, +3 authors B. Oh
• Published 1 June 2001
• Biology
• Nature Structural Biology

Helicobacter pylori, an etiologic agent in a variety of gastroduodenal diseases, produces a large amount of urease, which is believed to neutralize gastric acid by producing ammonia for the survival of the bacteria. Up to 30% of the enzyme associates with the surface of intact cells upon lysis of neighboring bacteria. The role of the enzyme at the extracellular location has been a subject of controversy because the purified enzyme is irreversibly inactivated below pH 5. We have determined the crystal structure of H. pylori urease, which has a 1.1 MDa spherical assembly of 12 catalytic units with an outer diameter of ∼160 Å. Under physiologically relevant conditions, the activity of the enzyme remains unaffected down to pH 3. Activity assays under different conditions indicated that the cluster of the 12 active sites on the supramolecular assembly may be critical for the survival of the enzyme at low pH. The structure provides a novel example of a molecular assembly adapted for acid resistance that, together with the low Km value of the enzyme, is likely to enable the organism to inhabit the hostile niche.