InterPro domain: IPR008580

The PPPDE superfamily (after Permuted Papain fold Peptidases of DsRNA viruses and Eukaryotes), consists of thiol peptidases with a circularly permuted papain-like fold. They contain a PPPDE domain which is a cysteine isopeptidase that exhibits a deSUMOylase activity in PPPDE2 (DeSI-1) and a deubiquinating activity in PPPDE1 (DeSI-2) and is described as a mixed alpha/beta-fold composed of six beta-strands and six alpha-helices. The catalytic dyad is formed by a conserved N-terminal histidine residue on beta2-strand and a conserved C-terminal cysteine residue on the following alpha3-helix (the H-C configuration). This catalytic dyad is invariably conserved in the PPPDE family of proteins [ 1 , 2 , 3 ].

1. Novel predicted peptidases with a potential role in the ubiquitin signaling pathway. Cell Cycle 3, 1440-50
2. Crystal structure of DeSI-1, a novel deSUMOylase belonging to a putative isopeptidase superfamily. Proteins 80, 2099-104
3. PPPDE1 is a novel deubiquitinase belonging to a cysteine isopeptidase family. Biochem. Biophys. Res. Commun. 488, 291-296