Are you sure of your spacegroup?
eleanor
Check for Se by doing an anomalous difference map using the PHIC FOM
output by refmac.
You will have to CAD together the two files - one with the Dano from the
data processing with the REFMAC output before doing the map.
eleanor
Sampath Natarajan wrote:
Dear all,
Now I'm solving a structure with 1.6A resolution. The data seems good with
R-sym (12.4) and all other parameters. Actually the data was collected with
SAD phasing. When we checked the data we couldn't find the Se atom in the
structure. Since the data resolution is good, we tried to do molecular
replacement using Balbes program. It was selected a model with 25% sequence
identity and we got the good solution too. I could find all residues in the
density and also checked the Ramachandran map which shows almost all
residues are in the allowed region.
The problem is, I have done refinement many times, the R-factor (45.3) and
R-free (51.4) is not reducing during the refinement and also figure of merit
is not increasing. Still it remains what I got during the first refinement.
The density is also not improving much. Also I could find many cuts in the
density.
My question is……..
1. Can we use SAD phasing data for MR solution?
2. Is there any other way to reduce the R/R-free?
3. Why the figure of merit is not increasing even after modeled the
residues exactly into the electron density?
Thanks,
Regards,
Sampath
