Aspergillopepsin_like, aspartic proteases of fungal origin.
The members of this family are aspartic proteases of fungal origin, including aspergillopepsin, rhizopuspepsin, endothiapepsin, and rodosporapepsin. The various fungal species in this family may be the most economically important genus of fungi. They may serve as virulence factors or as industrial aids. For example, Aspergillopepsin from A. fumigatus is involved in invasive aspergillosis owing to its elastolytic activity and Aspergillopepsins from the mold A. saitoi are used in fermentation industry. Aspartic proteinases are a group of proteolytic enzymes in which the scissile peptide bond is attacked by a nucleophilic water molecule activated by two aspartic residues in a DT(S)G motif at the active site. They have a similar fold composed of two beta-barrel domains. Between the N-terminal and C-terminal domains, each of which contributes one catalytic aspartic residue, there is an extended active-site cleft capable of interacting with multiple residues of a substrate. Although members of the aspartic protease family of enzymes have very similar three-dimensional structures and catalytic mechanisms, each has unique substrate specificity. The members of this family has an optimal acidic pH (5.5) and cleaves protein substrates with similar specificity to that of porcine pepsin A, preferring hydrophobic residues at P1 and P1' in the cleave site. This family of aspartate proteases is classified by MEROPS as the peptidase family A1 (pepsin A, clan AA).