3guq
Crystal structure of novel carcinogenic factor of H. pyloriCrystal structure of novel carcinogenic factor of H. pylori
Structural highlights
Publication Abstract from PubMedStomach 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. Structural basis for the Helicobacter pylori-carcinogenic TNF-alpha-inducing protein.,Tsuge H, Tsurumura T, Utsunomiya H, Kise D, Kuzuhara T, Watanabe T, Fujiki H, Suganuma M Biochem Biophys Res Commun. 2009 Oct 16;388(2):193-8. Epub 2009 Jul 28. PMID:19643085[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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