Helicobacter pylori HP0902 and related proteins, cupin domain
This family includes prokaryotic and archaeal proteins homologous to HP0902, a functionally uncharacterized protein from Helicobacter pylori and Spy1581, a protein of unknown function from Streptococcus pyogenes. These proteins demonstrate all-beta cupin folds that cannot bind metal ions due to the absence of a metal-binding histidine that is conserved in many metallo-cupins. HP0902 is able to bind bacterial endotoxin lipopolysaccharides (LPS) through its surface-exposed loops, where metal-binding sites are usually found in other metallo-cupins, and thus may have a putative role in H. pylori pathogenicity.