I have a case where a residue is in two alternative conformations for chain A and chain B. This residue (Arg 62) happens to be close to its NCS mate, such that only conformations A for both chains or only conformations B can take place at the same time.

I tried to follow guidance from the CNG newsletter 2015/07 and set up the constrained groups as shown below. However, the refinement crashes with an AtomSelectionError.

Any ideas what I could have done differently?

Cheers,

Jan

refinement {

 refine {

 occupancies {

 constrained_group {

 selection = chain A and resseq 62 and altloc A or \

             chain B and resseq 62 and altloc A or

 selection = chain A and resseq 62 and altloc B or \

             chain B and resseq 62 and altloc B or

 }

 }

 }

}

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