Dear Ursula,
I wouldnt be worried too much abot 4.4% Rsym to be honest. At this high
redundancy rather look on Rpim.
I once had a case with a low I/sI medium resolution shell where I had
strong translational NCS.
Is this the case?
Go publish!
Best, Matthias
-----------------------------------------
Dr. Matthias Zebisch
Division of Structural Biology,
Wellcome Trust Centre for Human Genetics,
University of Oxford,
Roosevelt Drive,
Oxford OX3 7BN, UK
Phone (+44) 1865 287549;
Fax (+44) 1865 287547
Email [email protected]
Website http://www.strubi.ox.ac.uk
-----------------------------------------
On 10/14/2013 7:23 PM, Ursula Schulze-Gahmen wrote:
I have a data set with high Rsym in the lower resolution ranges, and I
don't understand what is going on.
The crystal diffracts to about 3.0 A and has large cell dimension (
space group P6522 a= 185., c= 360.) Mosaicity is low. I processed the
data in P6522, solved the structure and refined it. The maps look good
and the structure refines very well to R/Rfree of 20.5, 23.5%.
But the dataset has a total Rsym of 22%, a redundancy of 20, an Rpim
of 7.6%, and CC1/2 of 0.55 in the highest resolution shell.
The problem seems to be in the lower resolution region around 8-5.5A.
The Rsym there is around 20%, it actually has a bump in this
resolution region and is slightly lower at 5.0 A before it steadily
increases to higher resolution. The high Rsym region between 8-5.5 A
correlates with very low I/sig which also increases again around 5.0 A
and then steadily decreases. The diffraction image shows very weak
spots too.
My question is: Is it likely that the data are processed correctly and
the crystal packing causes this strange diffraction pattern, or is
there something wrong with the data processing or the crystal?
Any suggestions would be greatly appreciated.
Ursula
--
Ursula Schulze-Gahmen, Ph.D.
Assistant Researcher
UC Berkeley, QB3
356 Stanley Hall #3220
Berkeley, CA 94720-3220
