Hello all,

I have encountered an issue while working with a protein in complex with ligands. There are some missing regions in the protein structure, and I attempted to model these regions using the "Model/Refine Loops" tool in UCSF Chimera (version 1.17.3). However, I observed that when I saved the modeled structures as PDB files, the ligands were not included in the file. Additionally, in some models, the modeled C-terminal extended into the binding pocket in an unusual manner.

I am curious whether this tool takes into account the presence of ligands or molecules in the structure while modeling missing regions. How can I prevent such issues from occurring? How can I model the missing long C-terminal in Chimera while ensuring that the presence of other ligands or molecules is also considered?

Thanks in advance.

Ece.