Experimental phasing with sticky triangles: how to deal with borderline cases

Phenix [1] is a Python-based software system for the solution and refinement of crystallographic structures using X-ray and/or neutron diffraction data.Recent developments in Phenix, especially in the refinement program phenix.refine, are presented.These include real space target functions for refinement, the use of torsion angle constraints, and the application of additional restraints to improve structure refinement at low resolution.The integration of automated side chain rotamer correction into the refinement process will also be described.