PA_PoS1_like: Protease-associated (PA) domain PoS1-like. This group includes various PA domain-containing proteins similar to Pleurotus ostreatus (Po)S1. PoSl, the main extracellular protease in P. ostreatus is a subtilisin-like serine protease belonging to the peptidase S8 family. Ca2+ and Mn2+ both stimulate the protease activity of (Po)S1. Ca2+ protects PoS1 from autolysis. PoS1 is a monomeric glycoprotein, which may play a role in the regulation of laccases in lignin formation. (Po)S1 participates in the degradation of POXA1b, and in the activation of POXA3, (POXA1b and POXA3 are laccase isoenzymes), but its effect may be indirect. The significance of the PA domain to PoS1 has not been ascertained. It may be a protein-protein interaction domain. At peptidase active sites, the PA domain may participate in substrate binding and/or promoting conformational changes, which influence the stability and accessibility of the site to substrate.
Jiyao W et al.(2023). "The conserved domain database in 2023.",