[ccp4bb]: Releasing aromatic restraints

[Brian Kelch]

Hello,

For certain reasons, I want to remove aromatic 
planarity restraints on sidechains of Phe 
residues in a 1.4Å structure.  I am using Refmac5 
in ccp4 suite6.0.1

Based on a previous recommendation from Eleanor 
Dobson (thank you!), I made a copy of the Phe.cif 
and set the aromatic planarity restraints to 0 
(or just removed them altogether).  I then 
performed TLS refinement with this library file 
for Phe assigned in LIBIN.  This actually didn't 
work because a control refinement without this 
library assigned in LIBIN gave the same exact 
results (both in terms of the model as well as 
all statistics).

Separately, I also tried turning off all aromatic 
restraints by going to the "Geometric Parameters" 
section of refmac in ccp4i, and changing the 
aromatic plane sigma from 0.02 to 0.  However, 
this had no effect (identical model and 
statistics again).  In fact, greatly increasing 
the sigma had no effect either.

The only time I was successful in turning of the 
aromatic planarity restraints was by changing the 
overall weight for all planarity restraints (both 
aromatics and peptides) to 0.  However, this has 
the unwanted effect of allowing the peptide bonds 
to lose their planar character.

Does anyone have a suggestion on what I could be 
doing wrong?  Is there some other way of turning 
the aromatic restraints off that I have not tried?

Thanks in advance,
Brian