... C-terminal domain in red. (B) Ribbon representation of the structure of the PSI domain of barley prophytepsin [25] (N-terminal domain,blue; C-terminal domain, red). (C) Model structure of the ... This protein family includessaposins, which are lysosomal sphingolipid-activator pro-teins [37], NK-lysin, granulysin, surfactant protein B,amoebapores and domains of acid sphingomyelinase andacyloxyacyl ... charac-terized by the presence of an extra protein domain of approximately 100 amino acids known as the plant specificinsert (PSI). This segment, inserted into the C-terminaldomain of the plant APs precursors,...