Hello everyone!

I'm calculating protein dimer structure in CNS-solve v1.21 using distance restraints obtained from solution NMR experiments.

There is an issue during calculation that most structures (not all) in the ensemble have two specific amino acids: one tyrosine and one phenilalanine broken like shown in the picture. The problem reproduces even after I remove all restraints associated with this amino acids.

I tried to review topology file, but did not find anything suspicious about these residues.

I would greatly appreciate if you could give me any hints on how to solve this problem.