| Type: | Family | Name: | Peptidase C58, Yersinia/Haemophilus virulence surface antigen |
| Description: | This group of cysteine peptidases correspond to MEROPS peptidase family C58 (clan CA). They are found in bacteria that include plant pathogens (Pseudomonas syringae), root nodule bacteria, and intracellular pathogens (e.g. Yersinia pestis, Haemophilus ducreyi, Pasteurella multocida, Chlamydia trachomatis) of animal hosts. The peptidase domain features a catalytic triad of Cys, His, and Asp. Sequences can be extremely divergent outside of a few well-conserved motifs. YopT, a virulence effector protein of Y. pestis, cleaves and releases host cell Rho GTPases from the membrane, thereby disrupting the actin cytoskeleton. Members of the family from pathogenic bacteria are likely to be pathogenesis factors [].Secretion of virulence factors in Gram-negative bacteria involves transportation of the protein across two membranes to reach the cell exterior. There have been four secretion systems described in animal enteropathogens such as Salmonella and Yersinia, with further sequence homologies in plant pathogens like Ralstonia and Erwinia []. The type III secretion system is of great interest, as it is used to transport virulence factors from the pathogen directly into the host cell and is only triggered when the bacterium comes into close contact with the host. The protein subunits of the system are very similar to those of bacterial flagellar biosynthesis. However, while the latter forms a ring structure to allow secretion of flagellin and is an integral part of the flagella itself, type III subunits in the outer membrane translocate secreted proteins through a channel-like structure [].Exotoxins secreted by the type III system do not possess a secretion signal, and are considered unique because of this []. Y. pestis secretes such a protein, YopT []. YopT is injected into the host cell upon contact, and is therefore considered to be a virulence factor. Haemophilus spp. express a similar toxin on their surface, a 76kDa antigen []. | Short Name: | Peptidase_C58 |
