This would be a possible explanation, and certainly is a problem with
low resolution refinements, but the free R indicates that overfitting
is not the problem here. (I'm assuming that the proper choice of test
set has been made in this case.) In my experience, for very isomorphous
pairs of str
On Mon, May 31, 2010 at 9:15 PM, Dale Tronrud wrote:
> One of the great mysteries of refinement is that a model created using
> high resolution data will fit a low resolution data set much better than
> a model created only using the low resolution data. It appears that there
> are many types o
One of the great mysteries of refinement is that a model created using
high resolution data will fit a low resolution data set much better than
a model created only using the low resolution data. It appears that there
are many types of errors that degrade the fit to low resolution data that
ca
This reminded me another thing... Did you create the free-R flags
considering twinning? This is very important.
Pavel.
On 5/31/10 12:43 PM, Gregory Bowman wrote:
Paul,
Does your lower resolution structure have the same unit cell as the
model used for MR? If your two crystals are the same ex
Paul,
Does your lower resolution structure have the same unit cell as the
model used for MR? If your two crystals are the same except for the
presence of the ligand, then you need to make sure to keep the same
Rfree set for both. Otherwise, some reflections that were previous in
the Rwork
Hi Paul,
another hypothesis...
If you take an ultra-high resolution structure from PDB (resolution
higher than 1.0A), then cut the data at 3A and do some refinement, you
will get unusually low R-factors.
This may suggest that your crystal can diffract to higher resolution and
3A is not the
Hi Paul,
I've seen that type of behaviour before for low resolution structures.
On such structures,
either I have a very hard time getting at the same time a good geometry,
"good" R-factors and satisfactory electron density,
or things go very smoothly and all the statistics (model geometry,
Hi everybody,
once more I need your help. I solved the structure of an enzyme at
resolution of 1.9 A. Now I was trying to get a complex and soaked some
ligand to my crystals. I could solve the structure (and see poor density for
my ligand or something else) at 3.0 A by molecular replacement using
