Hi Michel, I thought of a quick answer, though forgive me that I'm not Tristan. Have you tried first running the ChimeraX dssp command to assign the secondary structure, and next, choosing one of the secondary structure restraints buttons in the ISOLDE GUI's Restraints tab? -- Dan Richman, PhD (he/him/his) Research Associate, James Berger Lab Dept of Biophysics and Biophysical Chemistry Johns Hopkins University School of Medicine mobile: 201-669-0967 ________________________________ From: michel.thepaut--- via ChimeraX-users <chimerax-users@cgl.ucsf.edu> Sent: Wednesday, February 25, 2026 6:15 AM To: chimerax-users@cgl.ucsf.edu <chimerax-users@cgl.ucsf.edu> Subject: [chimerax-users] Re: ISOLDE and secondary structure restraints External Email - Use Caution Dear Tristan, I have a similar question then I exhume that topic... As I'm dealing with a ~1500 residues protein that I want to make dance in a density. Then as it is large I would like to use command lines to assign secondary structure to known helices and B-sheets instead of clicking on each residues to say this is an helix and this is a sheet. Is there a way to say to Isolde something like: 20 to 30 is an helix, 50 to 56 is a parallel sheet, ..., 1452 to 1460 is and helix. Please place your tensors and angles and lets dance?... Thank you for your answer. Michel _______________________________________________ ChimeraX-users mailing list -- chimerax-users@cgl.ucsf.edu To unsubscribe send an email to chimerax-users-leave@cgl.ucsf.edu Archives: https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.cgl.ucsf.edu%2Fmailman%2Farchives%2Flist%2Fchimerax-users%40cgl.ucsf.edu%2F&data=05%7C02%7Cd.e.richman%40jhu.edu%7C86c14a4715a841a3908a08de7482066f%7C9fa4f438b1e6473b803f86f8aedf0dec%7C0%7C0%7C639076299049509513%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=ktoCJWIvzmm8TE5Q7X8oNRleEyaGvE7iM6z9fWpzDXQ%3D&reserved=0<https://mail.cgl.ucsf.edu/mailman/archives/list/chimerax-users@cgl.ucsf.edu/>