From Proteopediaproteopedia link
Human Cyclophilin D Complexed with an Inhibitor
[PPIF_HUMAN] PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. Involved in regulation of the mitochondrial permeability transition pore (mPTP). It is proposed that its association with the mPTP is masking a binding site for inhibiting inorganic phosphate (Pi) and promotes the open probablity of the mPTP leading to apoptosis or necrosis; the requirement of the PPIase activity for this function is debated. In cooperation with mitochondrial TP53 is involved in activating oxidative stress-induced necrosis. Involved in modulation of mitochondrial membrane F(1)F(0) ATP synthase activity and regulation of mitochondrial matrix adenine nucleotide levels. Has anti-apoptotic activity independently of mPTP and in cooperation with BCL2 inhibits cytochrome c-dependent apoptosis. 
Publication Abstract from PubMed
X-ray crystallography is an established technique for ligand screening in fragment-based drug-design projects, but the required manual handling steps - soaking crystals with ligand and the subsequent harvesting - are tedious and limit the throughput of the process. Here, an alternative approach is reported: crystallization plates are pre-coated with potential binders prior to protein crystallization and X-ray diffraction is performed directly `in situ' (or in-plate). Its performance is demonstrated on distinct and relevant therapeutic targets currently being studied for ligand screening by X-ray crystallography using either a bending-magnet beamline or a rotating-anode generator. The possibility of using DMSO stock solutions of the ligands to be coated opens up a route to screening most chemical libraries.
Combining `dry' co-crystallization and in situ diffraction to facilitate ligand screening by X-ray crystallography.,Gelin M, Delfosse V, Allemand F, Hoh F, Sallaz-Damaz Y, Pirocchi M, Bourguet W, Ferrer JL, Labesse G, Guichou JF Acta Crystallogr D Biol Crystallogr. 2015 Aug 1;71(Pt 8):1777-87. doi:, 10.1107/S1399004715010342. Epub 2015 Jul 31. PMID:26249358
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.