|PROSITE documentation PDOC51276|
Pyrococcus furiosus protease I (PfpI) (EC 3.2.-.-) is an intracellular cysteine peptidase, characterized by its stability and proposed to represent the predominant proteolytic activity of this thermophilic archaebacterium. Pfpi-like proteins have been found in bacteria, archaea, in some plants and in amoebas.
The structure of P. horikoshii PfpI shows an α/β sandwich fold, which consists of a central β sheet flanked by two helices and two strands on one side, and by six helices and two strands on the other side (see <PDB:1G2I>). The fold resembles that of glutamine amidotransferases (GATase) of class I, which are characterized by a conserved Cys-His-Glu active site (see <PDOC00405>). The catalytically essential cysteine is located at a nucleophile elbow. PfpI forms a hexameric structure and the active sites are formed at the interfaces between three pairs of monomers. Cys and His form a triad with a glutamate residue from an adjacent monomer . Pfpi endopeptidases belong to the peptidase C56 family, which is classified with the peptidase C26 γ-glutamyl hydrolases (see <PDOC51275>) in the clan PC(C) [E1,E2]. Other peptidase C56 family proteins are structurally and functionally different , e.g. human DJ-1 creates a hydrophobic patch at the molecular interface instead of completing the catalytic triad, while E. coli chaperone HSP31 forms a Cys-His-Asp triad.
Some proteins known to contain a PfpI endopeptidase domain:
The profile we developed covers the entire PfpI endopeptidase domain.Note:
The PfpI endopeptidase domain profile is in competition with a profile of a related domain, i.e. GATase type 1 (see <PDOC00405>).Last update:
December 2006 / First entry.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Du X. Choi I.-G. Kim R. Wang W. Jancarik J. Yokota H. Kim S.-H.|
|Title||Crystal structure of an intracellular protease from Pyrococcus horikoshii at 2-A resolution.|
|Source||Proc. Natl. Acad. Sci. U.S.A. 97:14079-14084(2000).|
|2||Authors||Bandyopadhyay S. Cookson M.R.|
|Title||Evolutionary and functional relationships within the DJ1 superfamily.|
|Source||BMC Evol. Biol. 4:6-6(2004).|