Hi Almudena, you can do it with PyMOL, using PSICO's angle_between_helices with the "cafit" method. Example: run https://raw.githubusercontent.com/speleo3/pymol-psico/master/psico/orientation.py fetch 3pt6, async=0 as cartoon angle_between_helices chain D+J, chain I+C, cafit Hope that helps. Cheers, Thomas On 04 Mar 2015, at 13:04, Almudena Ponce Salvatierra <[log in to unmask]> wrote: > Hi everyone, > > I would like to ask if any of you know how to measure the angle between two nucleic acid helices? I am trying with pymol, but have not found a solution to it yet. > > Any ideas? > > Thanks a lot. > > Best, > > Almudena. -- Thomas Holder PyMOL Principal Developer Schrödinger, Inc.