PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides (By similarity). Histone chaperone possibly involved in H3/H4 deposition to the nucleosome. Associates with 18S rDNA chromatin and negatively regulates the level of its expression. [protein]-peptidylproline (omega=180) = [protein]-peptidylproline (omega=0) Interacts with histone H3. A number of isoforms are produced. According to EST sequences. Broadly expressed in leaves, flowers, stems and roots. Detected in root apical meristem region and pollen. Belongs to the FKBP-type PPIase family.