I have a structure I am trying to finish in Phenix.refine

The is one problem: a glutamate residue sitting on a crystallography 2-fold axis

with partial occupancy (picture attached). This residue and its symmetry mate appear to take turns sitting

at this position: filling the density leads to severe collision with its symmetry mate.

Building the side-chain with occupancy 0.5 doesn’t seem to help, as the residue is pushed

out of density during refinement.

Any work-arounds?

Thanks all,

Aaron