PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. Involved in pre-mRNA splicing (By similarity). [protein]-peptidylproline (omega=180) = [protein]-peptidylproline (omega=0) Associated with the spliceosome. Belongs to the cyclophilin-type PPIase family. CWC27 subfamily.