I have constructed model of pentameric protein by exchanging one of the chains with a very closely related chain from other variant of such pentameric protein. Chimera recognizes that my model consists of parts of two proteins. I would like to save it as a single protein file. When I attempt to save model as a single file (option in save dialog) a PDB file is produced. However, when I open this file in other application (such as Cresset Flare) to explore molecular dynamics or docking in this newly constructed hybrid system - it opens as two different proteins. Is it possible to “merge” the parts to become a single pentameric protein, that would behave as single entity during docking or MD computations? Jacek Jagodzinski PS. I am not computational chemist, I am medicinal chemist by training and long career.