Hi Bala, I believe you would need: sym #0 group #1 … assuming the template model #1 has biological unit information (REMARK 350 BIOMT) information in its header. <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/sym.html> If the template instead has symmetry information in other types of symmetry records, you may need to take a slightly longer approach: (a) show symmetry copies of the template, e.g. with the Unit Cell tool (b) open extra copies of your modeled protein (c ) superimpose the copies of the modeled protein onto those of the template. Probably the matchmaker approach would be easiest. <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/superposition.html> If the template does not have symmetry information in its header, you would need to somehow obtain a PDB file with the template already in the multimeric state (possibly hand-modeled) and then proceed with the third step above, or you could specify symmetry directly in the sym command with various keywords (group, axis, center…), but that can be difficult. I hope this helps, Elaine ---------- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco On Oct 29, 2013, at 7:52 AM, Bala subramanian <bala.biophysics@gmail.com> wrote:

Hello, 1) I have modelled one chain of a multimer. Since this is a modelled structure I dnt have any symmetry information in my pdb. In such case, how can I generate the symmetry related copies. Say I want to apply a fivefold symmetry along z-axis, how can I achieve it ?

2) I used a template structure from PDB to model my structure. What is the correct way to apply the symmetry of existing pdb model to my modeled chain.

I tried this as follows, I opened my model as #0 and then the template pdb structure #1 and tried the following sym command and obtained an error as '#0 has no biological unit info.'

sym #0 #1

Thanks, Bala