I am Praveen, a graduate student at UC Irvine. Hope you are doing well. I am using Chimera X. In my project, I have to join a protein to a peptide sequence via a peptide bond. I have loaded the PDB files of both the protein and the peptide sequence & I have identified where (between which atoms) the peptide bond has to be. After loading the PDBs, I use the following in the command line "select #1:12.A@C#2:1.A@N" (basically identifying the residue/atoms where the peptide bond has to be formed) to join but I get the error "Expected an objects specifier or a keyword" . I am sorry if this is a common error and I have missed something, I am new to Chimera. Also it would be great if someone could tell me if there is a way to save the final pdb after joining them? 

Thank you so much for your time, 

Best, 

Praveen