HP0902 from Helicobacter pylori is a thermostable, dimeric protein belonging to an all-β topology of the cupin superfamily

Here, we report the first biochemical and structural characterization of the hypothetical protein HP0902 from Helicobacter pylori, in terms of structural genomics. Gel-permeation chromatography and dynamic light scattering indicated that the protein behaves as a dimer in solution. Circular dichroism spectroscopy showed that HP0902 primarily adopts a beta-structure and the protein was highly thermostable with a denaturing temperature higher than 70 degrees C. Finally, the backbone NMR assignments were obtained on the [(13)C,(15)N]HP0902 and the secondary structure was determined using the chemical shift data. Additionally, the local flexibility was assessed via a heteronuclear (1)H-(15)N steady state NOE experiment. The results revealed that HP0902 would adopt a compactly folded, all-beta topology with 11 beta-strands. All of the results clearly support the notion that HP0902 belongs to the cupin superfamily of proteins.