Modeling, Synthesis and Characterization of Phospho–Penta–Peptide derived from PKA RII Sub Unit: A Candidate Substrate for CaN Assay

Abstract

Calcineurin (CaN) plays an important role in many pathological conditions like cancer, metabolic aberrations and neurodegenerative disorders. Till date contemporary methods to assay CaN uses p-nitrophenylphosphate (p-NPP) and specific protein phosphatases 2B inhibitor or use of phospho-peptide substrate derived from protein kinase A (PKA) regulatory sub unit type PKARII. Here we have modeled a series of small phospho peptides derived from PKARII and were docked by Molegro Virtual Docking software to find out the binding free enegy and to determine the affinity with modeled Calcineurin catalytic subunit A (CaN A). Further the candidate phospho–penta–peptide (PPP) derived from PKA regulatory sub unit type II was synthesized in house by employing Fmoc chemistry by solution phase method, purified over HPLC and characterized by mass spectrometry. This PPP was employed to assay CaN activity by Malachite Green method found to be a candidate substrate for CaN.