Hi Dan, I cannot reproduce this behavior. The following commands result in residue 2 of the built peptide being changed to lysine: build start peptide "custom built" ASHNG -57.0,-47.0 -57.0,-47.0 -57.0,-47.0 -57.0,-47.0 -57.0,-47.0 rotLib Dunbrack select /A:2@O swapaa sel LYS Perhaps you could use Help→Report A Bug to submit a bug report about how to reproduce your problem…. --Eric Eric Pettersen UCSF Computer Graphics Lab
On Jul 20, 2026, at 11:17 AM, Daniel Gurnon via ChimeraX-users <chimerax-users@cgl.ucsf.edu> wrote:
Hi all, I occasionally use ChimeraX's "build structure" to construct short peptides to use in teaching. For efficiency's sake, it would be nice if I could take things I've already built and "mutate" an amino acid using the swapaa command. However, when I try to do this using a custom built structure (for example, selecting the residue I want to change, and then executing swapaa sel arg), I get the error "No amino acid residues specified for swapping".
The command works for downloaded structures, just not the custom ones. Is there a missing attribute that swapaa checks for, that isn't created when you make a custom peptide?
Dan ____________________________
Daniel Gurnon, Ph. D. Associate Professor of Chemistry and Biochemistry DePauw University Greencastle, IN 46135 _______________________________________________ ChimeraX-users mailing list -- chimerax-users@cgl.ucsf.edu To unsubscribe send an email to chimerax-users-leave@cgl.ucsf.edu Archives: https://mail.cgl.ucsf.edu/mailman/archives/list/chimerax-users@cgl.ucsf.edu/