Guess I could have determined that before posting the prior comment.
Hm, I'm having trouble reproducing this. Can you share your solution with scientists?
The three designable loops are not locked in place at all. You should have complete freedom to move them around and even separate them from the protein (but the should score poorly if you extend the cutpoints).
However, that range of residues (46-65) should be completely fixed. (Note that, if any residues have been inserted into your solution then the numbering will be off. It will be easier for us to debug the shared solutions.)
I can get my 44-63 residues to move by idealizing residues 27-43. They appear to return from where they came from but have uploaded my current solution for someone to check out as I did make a nice score gain around that time.
Uploaded two solutions one is my current high score and the other is after idealizing res. 27-43.
Happy to answer any further questions
Thanks for the feedback, all! It seems that some of these problems (see here) were related to solution sharing. When you encountered this bug, were you working with a solution that was shared from the previous aflatoxin round (Puzzle 1590b)?
We've closed this puzzle and reposted it with sharing disabled, as Puzzle 1597: Aflatoxin Challenge: Round 12b. If you continue to encounter these problems in the new puzzle, please let us know!
Mars has put up a sponsored feature on this in a recent edition of Nature (one with a picture of a cuttlefish on the front cover).
It's online at https://www.nature.com/articles/d42473-018-00170-5
... the fixed part of the protein isn't fixed. The part between the loops we could modify before, and the new one we could modify (the one fastened at both ends), came loose when I was pulling on the latter loop. Probably not what you intended.