InterPro domain: IPR023302

This entry represents the beta-propeller domain found at the N-terminal of prolyl oligopeptidase from the MEROPS peptidase family S9A. The prolyl oligopeptidase family consist of a number of evolutionary related peptidases whose catalytic activity seems to be provided by a charge relay system similar to that of the trypsin family of serine proteases, but which evolved by independent convergent evolution. The N-terminal domain of prolyl oligopeptidases form an unusual 7-bladed beta-propeller consisting of seven 4-stranded beta-sheet motifs.

Prolyl oligopeptidase is a large cytosolic enzyme involved in the maturation and degradation of peptide hormones and neuropeptides, which relate to the induction of amnesia. The enzyme contains a peptidase domain, where its catalytic triad (Ser554, His680, Asp641) is covered by the central tunnel of the N-terminal beta-propeller domain. In this way, large structured peptides are excluded from the active site, thereby protecting larger peptides and proteins from proteolysis in the cytosol [ 1 ].

1. Prolyl oligopeptidase: an unusual beta-propeller domain regulates proteolysis. Cell 94, 161-70