Dear all, I combined a PDB file from three chains to single chain format. In between those chains are TER. Now i need to add missing residues as SEQRES. I added them all properly, all atoms are named properly but chimera detects a missing residue at last position instead of the first position of chain B making the whole sequence shift for 1 nucleic acid residue to the left. Pymol, which does not read SEQRES, registers all missing residues as blanks and their positions are 100% correct (checked 3 times). SEQRES was copied from the three-chain PDB file and edited to resemble a single chain file (C and E were renamed to A, SEQRES numbering was continued uninterrupted). How does chimera read SEQRES? Here is the full pdb file in gist: https://gist.github.com/danilob2929/34c303a5b1981f0a60942bc322052672 Thanks in forwards, D.B.