Hi Florian,
I haven't done this but would like to comment on the generally
interesting idea. If the NMR data are measured on the same crystal
form, I would expect a general correlation between both parameters.
The absolute scale of B factors from different resolutions will vary,
but you scale it down or up I guess. However, in comparison to
relaxation data collected using solution NMR, there's the problem of
crystal contacts which influence the crystallographic B-factors and,
most likely, the solid state relaxation data. If you have two chains
of the same protein in a crystal, both in different environments, you
will find different B-factors are used for the refinements of these
two chains (which might be averaged in your solid state NMR analysis),
reflecting the fact that different parts of the two chains are
rigidified by crystal contacts. So basically the whole analysis will
be biased by crystal contacts and therefore seems problematic if you
are after the dynamic properties in solution. If that's not what you
are after than I would suggest a protein that comes with one chain per
ASU.
Regards,
Bärbel
Quoting Florian Schmitzberger <schmitzber...@crystal.harvard.edu>:
Hi everybody,
Has anybody looked at possible correlation of B factors, derived
from crystal structures of proteins, with relaxation parameters
measured by NMR on the same type of crystals (solid-state NMR of
crystals). The NMR parameters concerned are Rh1 and Rho1, which are
a measure of mobility on the time-scale of picoseconds to
milliseconds. Is it sensible to expect a general correlation of
these parameters with the crystallographic B factor? B factors
include a range of effects including static disorder, mobility, and
crystalline heterogeneity, whereas the relaxation parameters is a
measure of the molecular motion. Does it make sense to compare the
same protein structure from different crystal forms, determined at
different resolutions (and thus necessarily different B factors),
and try to directly correlate with corresponding measurements of NMR
relaxation parameters?
Regards,
Florian
--
Bärbel Blaum, Ph.D.
Interfakultäres Institut für Biochemie (IFIB)
Hoppe-Seyler-Strasse 4
D-72076 Tübingen
Germany
+49 70 71 29 73 375
