Family C70


Summary Holotypes Alignment Tree Genomes Literature

Summary for family C70

Family type peptidaseC70.001 - AvrRpt2 peptidase (Pseudomonas syringae), MEROPS Accession MER0027409 (peptidase unit: 72-255)
Content of familyPeptidase family C70 contains a putative bacterial peptidase.
History Identifier created: MEROPS 7.0 (4 April 2005)
The plant pathogen Pseudomonas syringae secretes disease-causing factors into the host cell via its type III secretion pathway (Hotson & Mudgett, 2004). One of these factors is the protein AvrRpt2, and there is evidence that this is a cysteine peptidase (Axtell et al., 2003). When the protein enters the plant cell it is cleaved and the RIN4 protein of the host plant cell also disappears. The RIN4 protein is intimately involved in the pathogen-host interaction (Mackey et al., 2002).
Catalytic typeCysteine
Active site residuesC122 H208 D226 
Active siteA modelling study led to a sequence alignment of the AvrRpt2 protein with staphopain A (C47.001) in which Cys122, His208 and Asp226 (AvrRpt2 numbering) were aligned with residues of the catalytic triad of staphopain (Axtell et al., 2003). Mutation of Cys122, His208 or Asp226 abolished the in planta processing of AvrRpt2, and mutagenesis of Cys122 or His208 abolished the ability of AvrRpt2 to mediate elimination of the host RIN4 protein. Gln115 of AvrRpt2, preceding Cys122, appears to be located appropriately to function similarly to Gln152 in papain (C01.001).
Activities and specificitiesThere is evidence that endopeptidase activity of AvrRpt2 is responsible for its own autolytic cleavage at Gly71Gly72 and also for the elimination of the host RIN4 protein (Axtell et al., 2003; Axtell et al., 2003). The sites of cleavage in RIN4 match that in the peptidase itself (Chisholm et al., 2005).
Molecular structureOn the basis of the order of catalytic residues and the remote similarity to staphopain A (C47.001), AvrRpt2 is assigned to clan CA.
Distribution of family Bacteria details  
Archaea -  
Protozoa -  
Fungi -  
Plants -  
Animals -  
Viruses -  
Biological functionsActivities that are attributed to AvrRpt2 include its self-cleavage (which may well be an auto-activation), and the destruction of the host cell RIN4 protein. These activities could contribute to the pathogenic activity of Pseudomonas syringae.
Statistics for family C70Sequences:9
Identifiers with PDB entries:0
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Phylogenetic tree (Newick format)
Peptidases and Homologues MEROPS ID Structure
AvrRpt2 peptidaseC70.001-
family C70 unassigned peptidasesunassigned-