Hi Tom Thanks a lot. It showed that "No residues specific for swapping" when I work on my pdf, what should I do? By the way, the DNA is dsDNA, is there any way to replace the pair of DNA together? Best regards Gary From: Tom Goddard <goddard@sonic.net> Sent: Monday, July 26, 2021 11:21 AM To: gren@lbl.gov Cc: Azad, Roksana via Chimera-users <chimera-users@cgl.ucsf.edu> Subject: Changing DNA sequence Hi Gary, The swapna command lets you change a nucleic acid base, for example, to change residue 18 in chain C from a T to a G use open 1rsb swapna G :18.C Documentation for swapna https://www.cgl.ucsf.edu/chimera/current/docs/UsersGuide/midas/swapna.html Tom On Jul 26, 2021, at 1:31 AM, <gren@lbl.gov <mailto:gren@lbl.gov> > <gren@lbl.gov <mailto:gren@lbl.gov> > wrote: Dear Tom Thanks for many answers to our previous questions. I have one more question to our loved Chimera program. I have a NDA model (PDB), but the sequence is not right. Is there any way to use this DNA model to generate a new model with a right order of sequence? In other word, if is there an automatic/ simple method (by comment lines) to replace the sequence by the correct one in Chimera? Thanks a lot!! Gary Gang (Gary) Ren, PhD Lawrence Berkeley National Laboratory Molecular Foundry, Room: 2220 1 Cyclotron Road, MS 67R2206 Berkeley CA 94720-8197 Phone: (510) 495-2375; Fax: (510) 486-7268 Email: <mailto:gren@lbl.gov> gren@lbl.gov; <https://rengroup.lbl.gov/> https://rengroup.lbl.gov/