<p>This domain is found in almost all members of MEROPS peptidase family C25, (clan CD). Peptidase family C25 is a protein family found in the bacteria <taxon tax_id="837">Porphyromonas gingivalis</taxon> (Bacteroides gingivalis) a Gram-negative anaerobic bacterial species strongly associated with adult periodontitis. One of its distinguishing characteristics and putative virulence properties is the ability to agglutinate erythrocytes [<cite idref="PUB00006360"/>]. It is a highly proteolytic organism which metabolises small peptides and amino acids. Indirect evidence suggests that the proteases produced by this microorganism constitute an important virulence factor [<cite idref="PUB00006278"/>]. Protease-encoding genes have been shown to contain multiple copies of repeated nucleotide sequences. These conserved sequences have also been found in haemagglutinin genes [<cite idref="PUB00006414"/>].</p> Peptidase C25, Ig-like domain