I'm trying to predict the structure of a monoclonal antibody that does not have a crystal structure (and thus no PDB). I have the sequence for the heavy and light chain, and tried inputting it into Phyre2, but I wasn't sure how to treat the multiple chains. In the end, I just concatenated them both, which didn't seem to work as it told me the closest result was a glycoprotein.
How do I treat a protein such as an antibody, which is made up of multiple chains when predicting the structure?