Dear Tom, I have the same question too. Another simple question is that how can I merge two symmetry related molecule? Though I can easily expand them by coot. Best! Lu -- Lu Zuokun, Ph.D. Candidate College of Life Science, Nankai University 在 2015-11-18 23:14:48，"Terwilliger, Thomas Charles" 写道： Hi Ashok, If you have a PDB file with 2 crystallographically-related copies of your molecule, with one called chain A and one called chain B, you can run phenix.simple_ncs_from_pdb on your PDB file to find the matrices and translations. Let me know if that doesn't do it! All the best, Tom T From:[email protected] on behalf of Ashok Nayak Sent: Wednesday, November 18, 2015 7:58 AM To:[email protected] Subject: [phenixbb] (no subject) Hello Phenix BB, Like every amateur crystallographer I could easily generate symmetry mates in a given radius in coot, but I wondered always which is the crystallographic two fold axis axis(my space group being C2) through which the molecule is rotated and translated (if it is) to get the next molecule. I tried superpose to find the answer, but could only get the Euler angles and transformation matrix and not the axis. Are there any programs where I can get to know this, would be grateful to be enlightened for the same thanks BB in advance regards -- AshokNayak PhD student- Molecular and Structural Biology Division CSIR-CDRI, Janakipuram Extension Lucknow-226031 India