Hi Mohamed,
Did you try CSO or CSD?
I've seen oxidation of Cys residues in the active site of Cysteine-dependent
Phosphatases before.
In addition, oxidation is more easily explainable than CSS and SMC, especially
if reducing agents were omitted from final purification steps.
HTH,
Dave
--
Thanks for the suggestion about using NCS constraint to apply change on one
subunit to other subunits. That should make life much easier.
About the problem of phenix realspace refinement, I figured it out. I used
GUI and when I checked the log file, the "ramachandran_restraints" was
turned off.
Dear Hena,
You already have excellent advice but I would also look at the PEG smear
approach developed by Frank von Delft’s group – Chaikuad et al., Acta Cryst D.
7, 1627-39 (2015). It’s commercially marketed by Molecular Dimensions and has
features which may be amenable to complex systems.
I am working on a model at a resolution of 2.1 A. The active site Cys in both
copies have a positive density towards the S end of the residue and these blobs
are there in FEM and Polder maps. When I replace these residues with either CSS
or SMC, I get the following statistics. What is the best
Hena
There was a very interesting paper by Peter Sun and coworker from 2002.
They pointed out that there is a very strong bias towards crystallizing
protein-protein complexes with PEG rather than salt as the main precipitant.
Patrick
___
Radaev and Sun.
