I have a protein-DNA complex and would like to apply SS restraints. What is the best way to apply the SS restraints to the protein only, using the GUI? I have tried the following: Select ‘Use secondary structure restraints’ in the ‘Refinement Settings’ tab ‘Select Atoms’ In the Selection Editor window, 'Find Secondary Structures' Removed manually all nucleic acid restraints in ‘Base Pairs’ and Stacking Pairs’ tabs Save and close. However, phenix refinement keeps switching SS restraints for nucleic acids to True. Kind regards, Luca Luca Pellegrini, PhD Department of Biochemistry University of Cambridge Cambridge CB2 1GA United Kingdom [email protected] tel.: 0044 1223 760469 https://www.bioc.cam.ac.uk/pellegrini-group/pellegrini-group @PellegriniLab