| Primary Identifier | IPR046350 | Type | Homologous_superfamily |
| Short Name | Cystatin_sf |
| description | The cystatin superfamily comprises cysteine protease inhibitors that play key regulatory roles in protein degradation processes. This superfamily includes cystatins, cathelicidins, staphopains, kininogens, latexins and Secreted phosphoprotein 24 (Spp-24) []. The progenitor of this superfamily was most probably intracellular and lacked a signal peptide and disulfide bridges, much like the extant Giardia cystatin. A primordial gene duplication produced two ancestral eukaryotic lineages, cystatins and stefins. Stefins remain encoded by a single or a small number of genes throughout the eukaryotes, whereas the cystatins have undergone a more complex and dynamic evolution through numerous gene and domain duplications []. Members of this superfamily differ in amino acid sequence but they share a conserved fold, consisting of a five stranded anti-parallel β-sheet wrapped around a five-turn α-helix [, ]. |
