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 [log in to unmask]
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
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