PPIase that catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and may therefore assist protein folding. [protein]-peptidylproline (omega=180) = [protein]-peptidylproline (omega=0) Binds cyclosporin A (CsA). CsA mediates some of its effects via an inhibitory action on PPIase. Not developmentally regulated. Grows and develops almost normally, except for the production of tall fruiting bodies. Belongs to the cyclophilin-type PPIase family.