Hello, I want to check the secondary structure of protein at particular residues. Since dssp needs all main chain atoms, does the following command at the make_ndx prompt makes the correct index file? 5 | r 1 | r 10-11 |r 14-17 | r 20-21 | r 26-32 | r 42 | r 45 (Main chain atom of particular residues). regards, Paymon