On Friday, May 20, 2011 02:28:26 pm Mittal, Seema wrote:
> Hi All,
>
> I am currently working on a 3A resolution dataset. The scaled file shows the
> following statistics (scroll down to the end of this email). It is P212121
> space group with R merge of 8.8%.
Your data statistics look fine. In fact, it looks to me that your crystal is
probably yielding good data to considerably better resolution than 3A.
Why did you choose to cut it there?
> My question is : Is there a way to selectively use only the data with
> I/Sigma value of 2 and more for refinement?
That is a bad idea. By removing data you are throwing away information.
Noisy data is still better than no data.
good luck with your [probably better than 3A] structure,
Ethan
> And how do i achieve this using refmac? I am aware that this would come at
> the cost of compromising data completeness. Any suggestions/help would be
> greatly appreciated.
>
>
> Thanks much,
> Seema Mittal
> Department of Biochemistry & Molecular Pharmacology
> 970L Lazare Research Building
> University of Massachusetts Medical School
> 364 Plantation Street
> Worcester, MA 01605
>
>
>
>
>
> Shell I/Sigma in resolution shells:
> Lower Upper % of of reflections with I / Sigma less than
> limit limit 0 1 2 3 5 10 20
> >20 total
> 50.00 6.46 2.0 3.8 5.3 6.2 7.6 12.5 34.3 65.0 99.3
> 6.46 5.13 0.7 2.2 3.9 5.3 8.2 15.7 36.6 63.4 100.0
> 5.13 4.48 1.3 2.8 4.0 5.8 9.3 13.8 27.3 72.7 100.0
> 4.48 4.07 0.7 1.7 4.0 5.4 7.9 13.9 35.4 64.1 99.5
> 4.07 3.78 1.8 3.6 5.1 6.9 11.8 20.8 49.6 47.3 96.9
> 3.78 3.56 1.5 3.8 6.7 8.7 13.3 26.7 65.4 30.8 96.2
> 3.56 3.38 0.8 3.2 7.1 8.9 12.9 31.1 76.6 20.0 96.6
> 3.38 3.23 2.0 4.8 8.1 14.8 23.4 44.8 84.7 12.7 97.5
> 3.23 3.11 4.1 9.2 13.8 18.4 29.6 51.0 86.0 11.0 96.9
> 3.11 3.00 2.4 8.6 13.9 18.8 30.6 53.9 92.4 4.5 96.9
> All hkl 1.7 4.3 7.1 9.8 15.3 28.0 58.1 39.9
> 98.0
>
>
> Shell Lower Upper Average Average Norm. Linear Square
> limit Angstrom I error stat. Chi**2 R-fac R-fac
> 50.00 6.46 511.7 20.0 8.8 1.098 0.065 0.073
> 6.46 5.13 284.6 10.1 6.3 1.047 0.062 0.064
> 5.13 4.48 500.9 17.0 8.8 1.007 0.062 0.069
> 4.48 4.07 446.1 17.4 9.2 1.032 0.069 0.070
> 4.07 3.78 307.1 14.5 8.4 1.065 0.089 0.092
> 3.78 3.56 243.4 13.8 7.9 1.033 0.108 0.112
> 3.56 3.38 182.3 12.0 8.3 1.083 0.132 0.134
> 3.38 3.23 136.5 10.4 7.7 1.048 0.155 0.151
> 3.23 3.11 107.4 9.2 7.3 1.096 0.184 0.163
> 3.11 3.00 91.0 8.7 7.3 1.044 0.215 0.201
> All reflections 287.7 13.5 8.0 1.055 0.088 0.082
>
--
Ethan A Merritt
Biomolecular Structure Center, K-428 Health Sciences Bldg
University of Washington, Seattle 98195-7742
