Hello, If the bond already exists in the structure, for example the S-S bonds in PDB 1zni (insulin), you can use commands: select disulfide select up show sel ~sel These commands select the S-S bond, then increase selection to whole residues containing those bonds (since you don’t just want a bond by itself), then shows the selected atoms, then clears the selection. <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/select.html> <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/atom_spec.html#builtin> However, if your structure only has two S atoms that are in bonding distance but no bond between them, Chimera does not automatically draw a bond. You would have to select those two atoms and then add a bond manually, e.g. with Tools… Structure Editing… Build Structure, Adjust Bonds section, or with the “bond” command. <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/editing/editing.html#bond> <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/bond.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 Jun 19, 2018, at 5:57 AM, pengweiyucas <pengweiyucas@163.com> wrote:

Dear sir: I want to know how to show the disulfide bond ? Thank you !