The graph shows that the torsional energy of the drug-protein complex initially fluctuates around a value of 740 kcal/mol. This suggests that the drug-protein complex is initially in a stable configuration with a strong binding interaction between the protein and the ligand. However, the torsional energy then starts to increase over time. This suggests that the drug-protein complex is becoming less stable over time and that the binding interaction between the protein and the ligand is weakening.