Before revision:  Data obtained from MD were in good agreement with those obtained from quantum mechanical (QM) methods, but more interactions within the dynamics of the system were revealed than from QM. A strong correlation between the tumbling of the protein and the transitions of the X4 dihedral angle of the MTSL was observed with a consequent effect on the distribution of the nitroxide (NO) group in space and time .
After revision:  It was found that the activation loop oscillated between two conformational states separated by 7 Angstrom and the average structures obtained from the MD trajectories showed the MTSL exposed to the solvent and probing the C-lobe of the protein .