Elucidating the conformational dynamics of intrinsically disordered proteins (IDPs) regulated by post translational modifications (PTMs) such as phosphorylation is challenging. Tau is a well-known IDP found hyper-phosphorylated in Alzheimer’s disease (AD) in humans [1]. The proline-rich motif of tau(210-240) peptide directly interacts with several of it’s binding partners proteins such as BIN1, 14-3-3 etc. All atoms molecular dynamic (MD) simulation studies have been performed for apo and four phosphorylated (212pThr, 217pThr, 231pThr, 235pSer) tau(210-240) peptide using three different temperature variants (278K, 298K and 310K) and two different force field parameters (AMBER99SB-ILDN and CHARMM36m) with TIP4PD water model. These two force fields parameters combine with TIP4PD water model close to experimental observations for multiple IDPs and IDR found from our group previous studies [2, 3]. From our MD simulations we observed, these four-phosphorylations cause increase in compactness of the peptide. The binding of partner proteins like BIN1 with tau may be altered by the strong salt bridges, forming nearby lysine and arginine due to the phosphorylation [4]. Phosphorylation induces a strong structural transition, with tau(210-240) favouring a bent conformation. The MD simulation results were verified using NMR experimental parameters like chemical shift and 3J-coupling. The experimental part has been carried out by our collaborator Prof. Isabelle Landrieu [5].