Hi Camille, The coordinate files from the PDB are independent of each other and each has its own reference frame; unless a single structure contains a complex of the two proteins, any overlap or contact between them is just a coincidence. You can use existing mutational, biophysical, genomic data, etc., to begin to make a testable prediction of the interaction, but ChimeraX is not aware of any of this. Best wishes Kevin From: Chimera-users <chimera-users-bounces@cgl.ucsf.edu> on behalf of Lake, Camille (NIH/NIAID) [C] via Chimera-users <chimera-users@cgl.ucsf.edu> Date: Sunday, October 30, 2022 at 4:42 PM To: chimera-users@cgl.ucsf.edu <chimera-users@cgl.ucsf.edu> Subject: [Chimera-users] Question regarding protein-protein interactions in ChimeraX Hello, My name is Camille Lake and I have used ChimeraX to model proteins. I was wondering - if I load two completely separate proteins from PDB, what is the nature of their interaction as shown by ChimeraX? The two proteins I'm interested in, TIM-3 (5f71) and CEACAM1 (5dzl), are predicted to interact in the literature, but if I load them separately into ChimeraX, is this predicted interaction what displays automatically? It seems that they are, but I can't find anywhere on the web whether this is automatically done in ChimeraX. Other proteins I randomly add in generally keep far away from each other in space. Thank you, Camille Camille Lake, PhD Emerging Leaders in Data Science (ORISE) Fellow National Institute of Allergy and Infectious Diseases (NIAID) - Office of Data Science and Emerging Technologies (ODSET) National Institutes of Health (NIH) 5601 Fishers Lane, 6C5 Rockville, MD 20871 camille.lake@nih.gov 301-761-7976 ---------------------------------------------- The information in this e-mail and any of its attachments is confidential and may contain sensitive information. It should not be used by anyone who is not the original intended recipient. If you have received this e-mail in error please inform the sender and delete it from your mailbox or any other storage devices. The National Institute of Allergy and Infectious Diseases (NIAID) shall not accept liability for any statement made that are the sender’s own and not expressly made on behalf of the NIAID by one of its representatives.