Follow-up Comment #1, bug #20470 (project relax): The problem is the PDB ATOM record "Alternate location indicator". In the 1OGT PDB entry, there are alternate locations for a few amino acids. The internal relax PDB parser cannot currently handle this and it sees two residues. For example for residue 40, this causes the @N extraction to create two nitrogen spin containers for the single residue. The sequence.attach_protons user function can then not handle this. A temporary solution is to use the ScientificPython PDB parser. _______________________________________________________ Reply to this item at: <http://gna.org/bugs/?20470> _______________________________________________ Message sent via/by Gna! http://gna.org/