As Robbie says, in such a case I just blindly refine with local NCS
restraints - this should improve the greater part of the model and thus
provide you with clearer maps. It is quite common for different copies of
the monomer to have differences - after all the crystal environment will be
The fact that your protomers have different density levels does not mean they
are structurally different. The prior assumption should be that they are the
same unless proven otherwise. So I would keep the (local!) NCS restraints in
the initial stages and only remove them if it becomes apparent
Hello all
I am writing to request opinions from the community regarding the following:
*Situation:* An ASU comprising a non-crystallographic homo-octamer of a
biological monomer was obtained from MR. Electron density in the initial
2Fo-Fc, as well as Fo-Fc maps, seems to vary widely* across the
