Family C37
Summary for family C37
| Family type peptidase | C37.001 - calicivirin (Southampton virus), MEROPS Accession MER0002195 (peptidase unit: 1100-1272) |
| Content of family | Peptidase family C37 contains calicivirin, a polyprotein-processing endopeptidases known from caliciviruses. |
| History |
Identifier created: Perspect.Drug Discov.Des. 6:1-11 (1996)
Each virus in the calicivirus group of the picornaviruses encodes just a single peptidase in the ORF1 polyprotein, either of family C24 or C37. The function of the family calicivirin (C37.001) in Southampton virus was discovered by Martin Alonso et al. (1996) and further characterised by Liu et al. (1999).
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| Catalytic type | Cysteine |
| Active site residues | H1129 C1238 |
| Active site | The two essential catalytic residues are numbered His1129 and Cys1238 by MEROPS (see the Alignment). Cys1238 can be replaced by Ser without loss of activity. The highly-conserved Glu1153 between the two catalytic residues is not essential, being replaced by alanine without loss of activity (Someya et al., 2002; Nakamura et al., 2005). |
| Activities and specificities | P1 residues in the cleavage sites are commonly Glu or Gln, as for several other families in clan PA(C). The mechanism of substrate binding has been considered in the light of the structure of the Chiba virus peptidase (Nakamura et al., 2005). |
| Molecular structure | The structure of the peptidase (C37.001) from Chiba virus has been described (Nakamura et al., 2005). The chymotrypsin-like fold resembles those of other viral peptidases in subclan PA(C). |
| Clan | PA |
| Subclan | PA(C) |
| Basis of clan assignment | Predicted active site residues for members of this family and family S1 occur in the same order in the sequence: H, E/D, C/S. |
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Distribution of family
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