To investigate the structural dynamics and stability of protein-ligand complexes, molecular dynamics (MD) simulation was conducted using Gromacs version 2018 () . The simulation was done to compare SIRT1 with the vitamin D complex (holo) and the non-bonded Sirt1 (apo). Sirtuin 1 protein was selected based on its overall high binding affinity obtained in the molecular docking simulation. The protein topology was generated using the OPLS-AA force field and ligand topologies were generated using the LigPerGen tool . The systems were immersed in a cubic simulation box of 10.0 nm, 10.0 nm, and 10.0 nm dimensions with a distance of 1 nm from the edge of the box on both sides, solvated with the TIP4P water model , followed by the addition of 5 sodium counter ions at a concentration of 0.15 M for neutralization . The systems were energy minimized using the steepest descent algorithm to avoid artifacts with a convergence criterion of maximum force not greater than 1000 kJ/mol (𝐹max ≤ 1000 kJ/mol). Subsequently, the systems were equilibrated in a constant Number of particles, Volume, and Temperature (NVT), followed by a constant Number of particles, Pressure, and Temperature (NPT) both for 0.5 ns and a production run for 100 ns.