Hello, I have two PDB models I am comparing, but I am having some issues generating the seq_rmsd attribute across all of the chains in the superposition that I want. My current models (same protein, but different states and slightly altered built sequences) have chains A/B/C/D/E/F separated over two domains of A/B/C and D/E/F, for example. My problem is that domain D/E/F is much larger than the former and when I run a matchmaker command such as this: matchmaker #1/A/B/C/D/E/F to #2/A/B/C/D/E/F pairing ss show true I get the resulting superposition favoring the /D/E/F domain (larger RMSD values on A/B/C). This would be fine, however, I want to investigate RMSD variation in D/E/F relative to a fixed position of A/B/C. If I run the following command I only get pairwise RMSDs (seq_rmsd header) for the specified chains but lack those of the larger D/E/F domain as they are not included. matchmaker #1/A/B/C to #2/A/B/C pairing ss show true I look to Calculate the RMSD between paired residues of chains /A/B/C/D/E/F without moving the current structures (after ‘mmaker’ alignment to A/B/C) with the ‘align’ command but the ‘move’ option set to nothing: align #1/A/B/C/D/E/F toAtoms #2/A/B/C/D/E/F move nothing matchNumbering (or matchAtomNames also tested) true I believe the above is what I want with regards to superposition for the RMSD calculations, but the ‘align’ job does not appear to give a seq_rmsd header attribute once run, even though the log seems to suggest it does a pairwise residue alignment to calculate the RMSDs. (Possibly because it does not just look at the CA like matchmaker does?) Is there a way to generate seq_rmsd attributes from the ‘align’ command, or is there a way to have an equivalent ‘move nothing’ in ‘mmaker’? I am looking to use seq_rmsd information to color the model and I am using v1.6.1. Any help is much appreciated! Dan.