Before 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 .
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 methane-thiosulfonate spin label, introduced into the activation loop .