Hi Wim,
I think that the main question I would ask is how you calculate the
Wilson B factor with 3.0-3.5 A data ...
We have done a rather big study of about 12,000 structures and below
2.5 A, how you calculate the B can result to
major discrepancies. There is hardly a line to get the gradient
I should have given the precision that the problem remains unaffected
by a change of the resolution range (even if I use for example only 4.5
to 3 A resolution).
I am not using TLS and the data are quite isotropic. Rcryst values are
as expected for such a structure.
Anopther 3.5 A dataset does
Hi,
another possibility to avoid the problems Dirk is mentioning: mask the
beamstop correctly during data processing. Usually, each data
processing package has some tools for doing this (and sometimes even
an automatic procedure might actually work ... but I wouldn't rely on
it without checking).
This reminds me of a potential problem with low resolution data that
you might have: if any strong reflection (or a couple of them) is only
partially measured, because it is in the half-shadow of the beamstop,
then the measured intensity is too small, which in turn results in a
too low over
Then I think it is the problem of fitting the TF parameters into low
resolution data.
REFMAC tries to use the lowest ( < 9A) data to get the solvent B factor
and then after applying that correction to get an overall B.
Many Wilson plot programs only use the data from 4A out, with the belief
that
Dear Wim,
I suppose that the solvent content would influence the Wilson plot and
also the distribution of atoms in the unit cell, I would not be too
alarmed about the discrepancy.
Interestingly, the Wilson plot of the Fcalc values is about 60 A2 as for
Fobs in the output dataset.
As far as
Wim Burmeister wrote:
Dear all,
I have a 3 A structure refined with REFMAC which gives consistently
average atomic B-factors of 40 A2, whereas the B factor from a Wilson
plot is about 60 A2. Is there any explanation for such a discrepancy?
There are no obvious problems:
No twinning, spacegrou
Dear all,
I have a 3 A structure refined with REFMAC which gives consistently
average atomic B-factors of 40 A2, whereas the B factor from a Wilson
plot is about 60 A2. Is there any explanation for such a discrepancy?
There are no obvious problems:
No twinning, spacegroup P21 with two molecule
