Family C99


Summary Holotypes Alignment Genomes Literature

Summary for family C99

Family type peptidaseC99.001 - iflavirus processing peptidase (Ectropis obliqua picorna-like virus), MEROPS Accession MER0405119 (peptidase unit: 2194-2492)
Content of familyFamily C99 contains endopeptidases from RNA viruses
History Identifier created: MEROPS 9.9 (23 August 2013)
Polyprotein processing activity has been characterized from the Ectropis obliqua picorna-like virus (EoV), which is a member of the family Iflaviridae (order Picornavirales) (Ye et al., 2012). Viruses in family Iflaviridae infect invertebrates, and EoV infects the caterpillar of the tea looper moth, which is a serious pest in tea plantations.
Catalytic typeCysteine
Active site residuesH2261 D2299 C2383 
Active siteThe active site residues have been proposed to be His2261, Asp2299 and Cys2383. Replacement of Asp2299 for Ala reduced but did not abolish activity (Ye et al., 2012).
Activities and specificitiesThe peptidase releases itself from the viral polyprotein and cleavage occurs in trans. The optimal pH is 7.5 and raising or lowering pH destroys the proteolytic activity. Bonds cleaved have Gln or Gln in P1 and a small amino acid (Ala or Ser) in P1" (Ye et al., 2012).
InhibitorsActivity was reduced by PMSF and effectively abbrogated by p-chloromercuribenzenesulfonate, methyl methanethiosulfonate and NEM (Ye et al., 2012).
Molecular structureThe peptidase is located between the helicase and polymerase within the viral polyprotein (Ye et al., 2012). Although no tertiary structure has been solved, the fold is assumed to be similar to that of picornain 3C, and family C99 is included in clan PA, subclan PA(C).
Distribution of family Bacteria -  
Archaea -  
Protozoa -  
Fungi -  
Plants -  
Animals -  
Viruses details  
Biological functionsThe peptidase processes the viral polyprotein, releasing proteins that are essential for maturation of the virus.
Statistics for family C99Sequences:3
Identifiers with PDB entries:0
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Peptidases and Homologues MEROPS ID Structure
iflavirus processing peptidaseC99.001-
family C99 non-peptidase homologuesnon-peptidase homologue-