Family C32


Summary Holotypes Alignment Tree Genomes Structure Literature

Summary for family C32

Family type peptidaseC32.001 - equine arteritis virus-type cysteine peptidase (porcine reproductive and respiratory syndrome virus), MEROPS Accession MER0002116 (peptidase unit: 259-384)
Content of familyPeptidase family C32 contains a polyprotein-processing peptidase of arteriviruses, papain-like cysteine proteinase beta (PCP beta).
History Identifier created: Perspect.Drug Discov.Des. 6:1-11 (1996)
Catalytic typeCysteine
Active site residuesC276 H345 
Active sitePutative catalytic Cys and His residues have been identified by mutagenesis (Snijder et al., 1994; den Boon et al., 1995; Snijder et al., 2004) (see the Alignment).
Activities and specificitiesThere is indirect evidence that arterivirus PCP beta cleaves a GlyGly bond just C-terminal to the active site His residue. Cleavage is rapid in cis; no cleavage in trans has been detected (reviewed by Snijder et al., 2004).
Molecular structure
Basis of clan assignmentActive site residues for members of this family and family C1 occur in the same order in the sequence: C, H.
Distribution of family Bacteria -  
Archaea -  
Protozoa -  
Fungi -  
Plants -  
Animals -  
Viruses details  
Biological functionsPapain-like cysteine proteinase beta is the central member of an array of three cysteine peptidase domains in the N-terminal 500 residues of the arterivirus polyprotein. PCP alpha and PCP beta together constitute the Nsp1 protein of the virus. PCP beta is responsible for releasing the Nsp1 protein from the ORF1a polyprotein; PCP alpha (C31.001) then cleaves Nsp1 to release itself and the PCP beta that is presumably no longer active.
Statistics for family C32Sequences:29
Identifiers with PDB entries:1
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Phylogenetic tree (Newick format)
Peptidases and Homologues MEROPS ID Structure
equine arteritis virus-type cysteine peptidaseC32.001Yes
papain-like peptidase 1 beta (simian hemorrhagic fever virus)C32.002-
papain-like peptidase 1 gamma (simian hemorrhagic fever virus)C32.003-
family C32 unassigned peptidasesunassigned-