The mutational analysis from the static structure normally ignores short or long range conformational changes and they do not include the dynamic effects caused by thermal motions. The molecular dynamics simulations and molecular mechanics-Poisson-Boltzmann surface area calculations on the problem of imatinib resistance by various BCR-ABL mutations has been studied by Lee et al.,. Computational simulations can provide atomic level description of structural details, energy landscape, dynamic behaviours, and other properties which are difficult to be obtained from the experimental studies. Here, we report the MD simulations, solvated interaction energies free energy calculations of ponatinib with native and mutants of BCR-ABL kinase. We have also calculated the contributions from individual amino acid BEZ235 residues in the active site of all complexes to provide the molecular basis for inhibition. To our knowledge these Reversine studies have not been carried out before and our results provide detailed information about the molecular mechanisms of inhibition of native and various mutant BCR-ABL tyrosine kinases when bound to ponatinib. The native and mutant ABL kinase �C ponatinib complexes with explicit water molecules and sodium ions for charge neutralization were subjected to 25 ns MD simulations. The fourteen BCR-ABL mutants studied in this work collectively represent more than 95% of clinically observed mutations that are imatinib resistant. With the exception of T315I, most BCR-ABL mutations are inhibited by dasatinib and nilotinib. Ponatinib inhibits native and all mutant ABL kinases with high affinity, although some mutants have slightly greater inhibition than the others. The ATP competitive inhibitors of ABL kinase are classified into DFG-in or DFG-out classes depending on their binding interactions with kinase domain. Ponatinib binds to ABL kinase domain with a DFG-out conformation and serves to distribute binding energy over a wide range of amino acid residues in the active site as shown in Figure 1. The presence of such optimized and distributed binding interactions has the potential to allow ponatinib to withstand modest reduction in potency caused by single mutation. For our convenience; we grouped these mutations by the region of their location in ABL kinase structure. These regions include the P-loop mutants M244V, G250E, Q252H, Y253F, Y253H, E255K, and E255V; gatekeeper residue mutants T315A and T315I; hinge region mutants F317L and F317V; activation loop mutant H396P and other mutants M351T and F359V. The location of mutations in BCR-ABL kinase is shown in Figure 2. In the ABL kinase, amino acid residues Tyr253, Thr315, Phe317 and Phe359 are located in close contact with ponatinib and therefore affect the binding and activity of inhibitor. The Ploop mutant residues Gly250, Gln252 and Glu255 are not in direct contact with ponatinib, but share non-bonding interactions with inhibitor. The rest of the mutations Met244, Met351 and His396 are located away from inhibitor binding site, but intriguingly display ponatinib based inhibition. SIE calculations from MD trajectories measure the free energy of complex formation. Table 1 shows the calculated free energies for native and 14 mutant BCR-ABL �C ponatinib complexes. The intermolecular vdW, intermolecular coulomb and change in surface area are shown in Table 1. This table indicates that IC50 values vary from 0.5 nM to 36 nM and SIE values calculated from this work are in the range 210.03 kcal/mol to 210.67 kcal/mol. Though there is no direct correlation between IC50 and SIE values, it can be observed that their respective values lie within a narrow range. Many patients eventually developed imatinib resistance, usually associated with above mentioned mutations in ABL kinase domain that either directly or indirectly effects the binding affinity of imatinib to ABL. The most common gatekeeper residue mutation T315I that accounts for 15�C20% of clinically observed mutations is completely resistant to imatinib, nilotinib and dasatinib. Native and T315I BCR-ABL kinases complexed with dasatinib are subjected to 25 ns of MD simulations and SIE binding free energies are calculated. The analysis of dasatinib complexed with native and T315I mutant BCR-ABL kinases revealed that native complex has relatively higher SIE free energy than when complexed with T315I that signifies the greater affinity of dasatinib for native compared to mutant BCR-ABL kinase.