1. Interactions among the sevenHelicobacter pyloriproteins encoded by the urease gene cluster
- Author
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David L. Weeks, Petra Voland, Elizabeth A. Marcus, George Sachs, Christian Prinz, and David R. Scott
- Subjects
Electrophoresis ,Gram-negative bacteria ,Urease ,Physiology ,Spirillaceae ,Two-hybrid screening ,In Vitro Techniques ,Microbiology ,Gastric Acid ,Bacterial Proteins ,Two-Hybrid System Techniques ,Physiology (medical) ,chemistry.chemical_classification ,Helicobacter pylori ,Hepatology ,biology ,Membrane transport protein ,Cell Membrane ,Gastroenterology ,Membrane Transport Proteins ,Phosphate-Binding Proteins ,biology.organism_classification ,Precipitin Tests ,Enzyme ,Biochemistry ,chemistry ,Mutagenesis ,biology.protein ,Carrier Proteins ,Bacteria - Abstract
Survival of Helicobacter pylori in acid depends on intrabacterial urease. This urease is a Ni2+-containing oligomeric heterodimer. Regulation of its activity and assembly is important for gastric habitation by this neutralophile. The gene complex encodes catalytic subunits ( ureA/B), an acid-gated urea channel ( ureI), and accessory assembly proteins ( ureE–H). With the use of yeast two-hybrid analysis for determining protein-protein interactions, UreF as bait identified four interacting sequences encoding UreH, whereas UreG as bait detected five UreE sequences. These results were confirmed by coimmunoprecipitation and β-galactosidase assays. Native PAGE immunoblotting of H. pylori inner membranes showed interaction of UreA/B with UreI, whereas UreI deletion mutants lacked this protein interaction. Deletion of ureE–H did not affect this interaction with UreI. Hence, the accessory proteins UreE/G and UreF/H form dimeric complexes and UreA/B form a membrane complex with UreI, perhaps enabling assembly of the urease apoenzyme at the membrane surface and immediate urea access to intrabacterial urease to allow rapid periplasmic neutralization.
- Published
- 2003