Before revision:  MD provided information about the conformational space of MTSL in the protein environment; an isotropic and uniform distribution of orientations of the spin label in space was found due to the large exposure of the activation loop to the solvent water.
After revision:  The main conformational states were determined using a clustering analysis routine within the AMBER software and the predominant modes of motion of the activation were determined performing a principal component analysis that revealed different degree of flexibility within the activation loop to the solvent water.