Hi, I am trying to make a comparative model using modeler. I downloaded my sequence from uniprot and a homolog protein from the pdb. I associated the sequence with the homologe and the alignment is okay however there are definitely regions where there is no match at all. So when I run modeler it fails with the following output: get_ran_648E> Alignment sequence does not match that in PDB file: 1 ./6opc_1.pdb (You didn't specify the starting and ending residue numbers and chain IDs in the alignment, so Modeller tried to guess these from the PDB file.) Suggestion: put in the residue numbers and chain IDs (see the manual) and run again for more detailed diagnostics. You could also try running with allow_alternates=True to accept alternate one-letter code matches (e.g. B to N, Z to Q). I have been trying to figure out how exactly to specify the chain IDs and residue numbers but I really didn’t get it. May I ask you to provide an example please? Best, David