Family C50
Summary for family C50
| Name | Peptidase family C50 (separase family) |
|---|
| Family type peptidase | C50.001 - separase (yeast-type) (Saccharomyces cerevisiae), MEROPS Accession MER0010982 (peptidase unit: 996-1629) |
| Content of family | Peptidase family C50 contains endopeptidases. |
| History |
Identifier created: MEROPS 5.00 (20 April 2000)
Genes encoding separase (C50.001) were originally discovered by genetic analysis of mitosis in fungi (e.g. Baum et al., 1988). These genes encode large proteins with conserved sequences near the C-termini that were recognised as homologous to peptidases in clan CD (Uhlmann et al., 2000). The peptidase was first termed separin and later separase. |
| Catalytic type | Cysteine |
| Active site residues | H1505 C1531 |
| Active site | The active site consists of a His, Cys catalytic dyad. The histidine occurs within a Xaa-Xaa-Xaa-Xaa-Gly-His-Gly motif, and the cysteine within a Xaa-Xaa-Xaa-Gly-Cys-Ser-Ser motif, in which Xaa is a hydrophobic residue (see the Alignment). These motifs are characteristic of clan CD. |
| Activities and specificities | Recombinant yeast separase cleaves the protein Scc1 in vitro, and separase purified from human cells is also capable of cleaving human Scc1. All bonds known to be hydrolysed by separase have Arg in P1 and an acidic residue in P4; there is also a preference for an acidic residue in P6 (Peters & Nasmyth, 2004). |
| Inhibitors | The protein securin provides regulation of the activity of separase in vivo: it is an inhibitor, but also is necessary for the activation of separase and for its correct location in the cell (Hornig et al., 2002). |
| Molecular structure | The peptidase unit is found at the C-terminus of proteins in the family; the N-terminal parts show little conservation of sequence. |
| Clan | CD |
| Basis of clan assignment | Active site residues for members of this family and family C14 occur in the same order in the sequence: H, C. |
