Family S65


Summary Holotypes Alignment Genomes Literature

Summary for family S65

Family type peptidaseS65.001 - picornain-like cysteine peptidase (Breda-1 torovirus) (Breda virus), MEROPS Accession MER0044929 (peptidase unit: 3131-3395)
Content of familyPeptidase family S65 contains endopeptidases.
History Identifier created: MEROPS 9.7 (1 August 2012)
Toroviruses are single stranded RNA viruses related to coronaviruses which infect vertebrates. The genome encodes a very large non-structural polyprotein which is processed by a serine peptidase that is a component of the polyprotein (non-structural protein 4).
Catalytic typeSerine
Active site residuesH3184 E3222 S3291 
Active siteA catalytic triad (His, Glu, Ser) has been predicted by comparison with other members of clan PA. In the peptidase from the Breda virus, Ser3184 has been identified by site-directed mutagenesis. However, substitution of the catalytic Ser for Cys retained partial activity (Smits et al., 2006). Other components of a catalytic triad are predicted to be His3184 and Glu3222, but mutagenesis of Glu3222 did not affect activity (Smits et al., 2006).
Activities and specificitiesProcessing of the polyprotein occurs at Phe-Xaa-Xaa-Gln consensus sequences (Smits et al., 2006).
Molecular structureNo tertiary structure for any member of the family has been solved. Family S65 is included in clan PA because the putative active site residues are in the same order in the linear sequence as in other members of the clan, and it is included in subclan PA(S) because the putative nucleophile is the hydroxyl of a serine.
Distribution of family Bacteria -  
Archaea -  
Protozoa -  
Fungi -  
Plants -  
Animals -  
Viruses details  
Biological functionsThe Breva-1 torovirus picornain-like cysteine peptidase processes the non-structural polyprotein to release individual proteins.
Statistics for family S65Sequences:2
Identifiers with PDB entries:0
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Peptidases and Homologues MEROPS ID Structure
picornain-like cysteine peptidase (Breda-1 torovirus)S65.001-
family S65 unassigned peptidasesunassigned-