3GUQ

Crystal structure of novel carcinogenic factor of H. pylori

Summary for 3GUQ

• Entry DOI: 10.2210/pdb3guq/pdb
• Descriptor: Putative uncharacterized protein (2 entities in total)
• Functional Keywords: tnfa inducing factor, long alpha helix, novel carcinogenic factor, toxin
• Biological source: Helicobacter pylori (Campylobacter pylori)
• Total number of polymer chains: 1
• Total formula weight: 19046.84

Authors

Tsurumura, T.,Tsuge, H.,Utsunomiya, H.,Kise, D.,Kuzuhara, T.,Fujiki, H.,Suganuma, M. (deposition date: 2009-03-30, release date: 2009-09-22, Last modification date: 2024-03-20)

Primary citation

Tsuge, H.,Tsurumura, T.,Utsunomiya, H.,Kise, D.,Kuzuhara, T.,Watanabe, T.,Fujiki, H.,Suganuma, M.
Structural basis for the Helicobacter pylori-carcinogenic TNF-alpha-inducing protein.
Biochem.Biophys.Res.Commun., 388:193-198, 2009

PubMed Abstract: Stomach cancer is strongly associated with infection by Helicobacter pylori. In 2005, we identified a new H. pylori gene encoding a TNF-alpha inducing protein (Tipalpha) that acts as a carcinogenic factor. Tipalpha is secreted from H. pylori as a homodimer whose subunits are linked by disulfide bonds. We also characterized a Tipalpha deletion mutant (del-Tipalpha) that lacks the N-terminal six amino acid residues (LQACTC), including two cysteines (C5 and C7) that form disulfide bonds, but nonetheless shows a weak ability to induce TNF-alpha expression. Here we report that del-Tipalpha has a novel elongated structure containing a 40-A-long alpha helix, and forms a heart-shaped homodimer via non-covalent bonds. Moreover, their circular dichroism spectra strongly suggest that the structures of the del-Tipalpha and Tipalpha homodimers are very similar. del-Tipalpha's unique mode of dimer formation provides important insight into protein-protein interactions and into the mechanism underlying the carcinogenicity of H. pylori infection.

PubMed: 19643085
DOI: 10.1016/j.bbrc.2009.07.121

Experimental method

X-RAY DIFFRACTION (2.47 Å)