On Sat, Jul 30, 2011 at 11:35 AM, Tatyana Sysoeva <tatyanasysoeva@gmail.com> wrote:
I am almost done repeating fix-rotamers run. First time it gave a way worse validation results then before running phenix without fix_rotamers=true.

This method behaves very poorly at low resolution - I ran some tests recently on a variety of 3.0-4.5A structures solved by molecular replacement, and while the rotamer fitting usually decreased the R-factor, it always made the clashscore much worse.  I wouldn't bother using it if you have worse than 3.0A data.

Model pdb contained the model identical to the control run but with added H atoms. I have not add H to the ADP molecules since I did not know how to write a correct CIF file for it.


If you use phenix.ready_set, it will handle the ADP molecules.

Interestingly in previous release version the same refinement runs produced:

without H clashscore = 77.580195/cbeta =8

with H clashscore = 119.729960/cbeta=330

We increased the weight on the nonbonded restraints 5x in the last few releases - this always improves the clashscore and Ramachandran statistics at low resolution, although it doesn't change the R-factors very much.  Still, 12% is an awful lot of Ramachandran outliers, even at that resolution.  If you're willing to experiment a little, try adding "ncs.type=torsion" to the parameters (without hydrogens) and let us know what happens.

-Nat