Dear all, My protein structure has 400 residues of which I want to calculate RMSD of particular 200 residues (approx) and they are not continuous. For example, from 34-70; 120-167; 180-210;.... For this how can I create an index file? Thank you -- *Regards,* *Rahul Suresh* *Research Scholar* *Bharathiar University* *Coimbatore*