| 1994 |
Peptidyl-prolyl cis-trans isomerase (PPIase) activity was detected in extracts of Plasmodium falciparum and was completely inhibited by cyclosporin A (CsA) at concentrations above 0.1 µM, but not by FK506 or rapamycin, indicating the activity is attributable to one or more cyclophilins (consistent with CYP19A/PF3D7_0322000). Furthermore, the P. falciparum cyclophilin-containing extract, in combination with CsA, inhibited the protein phosphatase activity of bovine calcineurin, suggesting the CYP19A–CsA complex can inhibit calcineurin. However, comparison of antimalarial vs. anti-isomerase activities of CsA analogues failed to show a correlation between PPIase inhibition and parasite growth inhibition. |
PPIase activity assay in parasite extracts; calcineurin phosphatase inhibition assay with bovine calcineurin; parasite growth inhibition assay with CsA analogues |
Biochemical pharmacology |
Medium |
7520696
|
| 1998 |
PF3D7_0322000 (PfCyP19, encoded by a gene on chromosome 3) was cloned, overexpressed in E. coli, and biochemically characterised. The recombinant protein displayed PPIase activity with kinetic constants Km >120 µM and kcat/Km = 1.2×10^7 M⁻¹ s⁻¹ using N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide as substrate. It bound CsA with high affinity (Kd = 13 nM, Ki = 6.9 nM). The protein has no signal peptide or N-terminal extension, suggesting cytosolic localisation. FK506 and rapamycin were inactive as inhibitors of its PPIase activity. CsA analogue Ki values correlated with residues 1 and 2 of CsA rather than residues 3 and 4, which instead correlated with parasite growth inhibition, suggesting the CYP19A–CsA complex presents residues 3–4 as an effector surface for a downstream target. |
Recombinant protein expression in E. coli; PPIase enzymatic assay (Michaelis-Menten kinetics); CsA binding assay (Ki determination); inhibitor SAR with CsA analogues; sequence analysis for localisation prediction |
The Biochemical journal |
High |
9716503
|
| 1995 |
A P. falciparum cyclophilin gene (PFCyP, consistent with PF3D7_0322000) was cloned with a 39-amino-acid N-terminal extension. Recombinant protein expressed in E. coli (with or without the N-terminal extension) was enzymatically active (PPIase activity) and sensitive to CsA inhibition. Northern blot analysis showed the gene is expressed in all erythrocytic stages, with highest expression in ring-stage parasites. |
Gene cloning; recombinant expression in E. coli; PPIase activity assay; Northern blot of synchronised parasite cultures |
Molecular and biochemical parasitology |
Medium |
8577319
|
| 2003 |
PfCyP-19A (PF3D7_0322000) was identified as one of the two major cyclosporin-binding proteins of P. falciparum by affinity chromatography on cyclosporin-Affigel followed by SDS-PAGE, Western blotting, and peptide mass fingerprinting. PfCyP-19A was confirmed to bind cyclosporin directly. (Note: the paper also characterised the sibling PfCyP-19B, but findings about PfCyP-19A are distinguished here.) |
Affinity chromatography on cyclosporin-Affigel; SDS-PAGE; Western blotting; peptide mass fingerprinting |
International journal for parasitology |
Medium |
12906882
|
| 2005 |
In CsA-resistant (CsAR) P. falciparum clones, mutations were detected in functionally significant amino acid residues of CYP19A (Cyp19A). One mutant CYP19A protein was purified and found to be unable to inhibit parasitic calcineurin in the presence of CsA, demonstrating that a functional CYP19A–CsA complex is required for calcineurin inhibition and that loss of this function is a mechanism of CsA resistance. |
Sequencing of CsAR parasite clones; purification of mutant CYP19A protein; in vitro calcineurin phosphatase inhibition assay |
Molecular and biochemical parasitology |
High |
15811524
|
| 2011 |
All eleven P. falciparum cyclophilin family members, including PF3D7_0322000 (CYP19A), were recombinantly expressed and purified using a common C-terminal His6-tag system. CsA-binding was assessed by thermal melt assay, providing comparative binding data across the family and confirming correct folding of CYP19A. |
Recombinant expression in E. coli; His-tag purification; thermal melt assay for folding and CsA binding |
Protein expression and purification |
Low |
21549842
|
| 2012 |
Among eight recombinantly produced P. falciparum cyclophilins assessed, only two displayed PPIase isomerase activity. All eight, including CYP19A (PF3D7_0322000), displayed molecular chaperone activity as measured by prevention of thermal aggregation of model substrates, suggesting CYP19A functions as a molecular chaperone in addition to its PPIase activity. |
Recombinant expression and purification of all family members; PPIase activity assay; thermal aggregation prevention (chaperone) assay with model substrates |
Molecular and biochemical parasitology |
Medium |
22546550
|
| 2015 |
Co-immunoprecipitation and yeast two-hybrid screening identified interaction partners of PfCYP19A (PF3D7_0322000) in P. falciparum. PfCYP19A was shown to interact with heat shock protein 70 (Hsp70). Additionally, treatment of parasites with CYP ligands disrupted transport of the rhoptry-associated protein 1 (RAP1), linking CYP19A function to protein trafficking. |
Co-immunoprecipitation; yeast two-hybrid screening; immunofluorescence/trafficking assay for RAP1 disruption upon CYP ligand treatment |
Parasitology |
Medium |
26156578
|
| 2022 |
Mass spectrometry-based interactome mapping of PP1c and its inhibitor 2 (I2) in P. berghei identified peptidyl-prolyl cis-trans isomerase (ortholog of PF3D7_0322000/CYP19A) as a component of the PP1c/I2 interactome in both asexual (schizont) and sexual (gametocyte) stages, suggesting CYP19A is a potential target of the PP1c/I2 complex. |
mCherry-tagged PP1c/I2 affinity pulldown from transgenic P. berghei parasites; mass spectrometry identification of interactors |
International journal of molecular sciences |
Low |
35162991
|