Hi Tim, You could either (1) use command "split" to split the existing model into separate chain models (or /A vs. everything else) For example, if existing model is #1 with chains A-D, command: split #1 ... will split it into model #1.1 with chain A, model #1.2 with chain B, etc. Close the extra models that you don't want. If you still need the original model you would just open another copy. Help for split: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/split.html> (2) simply delete everything that is not chain A, command: delete ~/A If you also still need the original model you would just open another copy. Help for delete: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/delete.html> See also how to specify atoms in the command line: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/atomspec.html> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

On Nov 14, 2022, at 7:19 PM, tim smith via ChimeraX-users <chimerax-users@cgl.ucsf.edu> wrote:

Hi All, I would like to create chain A as a separate model from the existing model. Could you please help me. Thank you. Best regards Tim