Molecular characterization of plasmodium vivax FK506-binding protein 25 (PvFKBP25).

Abstract

The emergence of drug-resistant Plasmodium parasites prompts for a search for new anti-malaria molecular targets. The immunosuppressive drug FK506 has been shown to bind to FK506 binding protein (FKBP) family and modulate cellular activities. Our lab has identified FKBP25 from Plasmodium vivax (PvFKBP25) and it is thought to be the molecular target of the drug. Thus, we aim to characterize this protein and examine its properties. Contrary to our hypothesis, results in this study have shown that PvFKBP25 does not bind to FK506. Hence PvFKBP25 is a non-canonical FKBP member although it shares sequence similarity to other FKBP family members. We also showed using NMR that PvFKBP25 binds to calmodulin in the presence of calcium ions in which calmodulin will aggregate in a dose-dependent manner. This result suggests a probable interaction of PvFKBP25 and calmodulin and that calmodulin can be a molecular target for drug design since it plays an important role in many crucial cellular processes.