Is the data anisotropic? This would explain the strange processing
statistics beyond 3.0 Angstrom. If using Dials directly it is worth
looking for abnormalities with the reciprocal lattice viewer.

I've seen similar issues with the completeness being low, when data is
weak in one direction, despite reflections being reported in the
scaling output.

It may also be worth running some analysis of the data with Staraniso
(https://staraniso.globalphasing.org/cgi-bin/staraniso.cgi) to try to
help.

Andy




Quoting Martin Malý <[email protected]>:

Dear Matt,

thank you for asking. I am bit confused how you set up the PAIREF
run. In paired refinement, data are added step by step - going to
higher resolution, i.e. lower d_hkl. So the merged data in the
PAIREF input should not be cut to much. The data statistics look
from DIALS quite strange, there is very good completeness and CC1/2
for high resolution shells, but very poor <I/sigma> and Rmeas.

I would suggest to refine the model at 3 A to be safe. Then, run
PAIREF with the initial resolution 3 A and using the cutoffs 2.8,
2.6, 2.4 and 2.2 A. Diffraction data must be up to 2.2 A in that
case, no truncation to 2.4 A as you mentioned previously.

I hope it will help. Please feel free to ask and let me know if it
was successful.

Best regards,
Martin


On 30. 09. 22 17:29, Matt McLeod wrote:
Hi all,

I am having a bit of trouble with PAIREF.  I am trying to determine
the resolution cutoff of a dataset which has a high Rwork
(0.223)/free (0.275)value for the resolution (2.24A).  I have
truncated this data further to 2.4A and the R values get better but
the electron density maps do not improve whatsoever.  When I put
this data into PAIREF I get this message.

WARNING: There are only 40 < 50 free reflections in the resolution
shell 2.75-2.70 A. Values of statistics Rfree and CCfree in this
shell could be misleading. Consider setting thicker resolution
shells.

This error occurs for all resolution bins.  Looking at the pdb log
of the refined structure (where the data looks quite reasonable,
maybe not a 2.3 dataset but not much worse).

REMARK   3  FIT TO DATA USED IN REFINEMENT (IN BINS).
REMARK   3   BIN  RESOLUTION RANGE  COMPL.    NWORK NFREE   RWORK
RFREE  CCWORK CCFREE
REMARK   3     1   60.08 -    4.28    1.00     4135   213  0.1646
0.2213   0.940  0.901
REMARK   3     2    4.28 -    3.40    1.00     4095   201  0.1951
0.2672   0.928  0.857
REMARK   3     3    3.40 -    2.97    1.00     4099   204  0.2736
0.3303   0.861  0.739
REMARK   3     4    2.97 -    2.70    1.00     4026   212  0.3486
0.3508   0.726  0.551
REMARK   3     5    2.70 -    2.51    0.78     3178   154  0.4027
0.4062   0.637  0.594
REMARK   3     6    2.50 -    2.36    0.29     1154    60  0.4118
0.3984   0.647  0.547
REMARK   3     7    2.36 -    2.24    0.01       29     1  0.3366
0.4089   0.343  0.000

Where I assume NFree is the issue, but doesn't suggest that there
arent enough reflections.  There needs to be a higher cutoff as the
completeness goes to pot, but the scaling log from DIALS suggested
it was at least a good starting point.

 Statistics by resolution bin:
         d_max  d_min   #obs  #uniq   mult.  %comp       <I>
<I/sI>    r_mrg   r_meas    r_pim   cc1/2   cc_ano
        118.81   5.97  10436   1577    6.62  99.94     797.6
22.8    0.110    0.120    0.046   0.992*  -0.397
          5.97   4.74   9602   1549    6.20 100.00     491.7
10.0    0.172    0.188    0.075   0.979*  -0.240
          4.74   4.14  10410   1528    6.81 100.00     513.5
10.3    0.191    0.207    0.079   0.978*  -0.281
          4.14   3.76  10833   1551    6.98 100.00     324.7
6.9    0.238    0.257    0.098   0.969*  -0.419
          3.76   3.49  10956   1526    7.18 100.00     207.5
4.6    0.259    0.280    0.105   0.975*  -0.271
          3.49   3.29  10899   1546    7.05 100.00     133.4
3.1    0.272    0.294    0.111   0.966*  -0.258
          3.29   3.12   9565   1528    6.26  99.93      86.9
2.0    0.314    0.343    0.136   0.935*  -0.346
          3.12   2.99   9256   1519    6.09 100.00      57.1
1.3    0.354    0.387    0.154   0.932*  -0.354
          2.99   2.87   9317   1524    6.11 100.00      43.6
1.0    0.403    0.441    0.177   0.934*  -0.198
          2.87   2.77  10087   1549    6.51 100.00      30.9
0.7    0.455    0.494    0.192   0.923*  -0.116
          2.77   2.69  10157   1524    6.66 100.00      26.4
0.6    0.503    0.546    0.210   0.927*  -0.132
          2.69   2.61  10351   1541    6.72 100.00      19.3
0.4    0.613    0.665    0.255   0.925*  -0.155
          2.61   2.54  10121   1504    6.73 100.00      15.5
0.4    0.735    0.797    0.306   0.906*  -0.088
          2.54   2.48  10510   1539    6.83 100.00      12.4
0.3    0.932    1.009    0.385   0.857*   0.006
          2.48   2.42  10432   1519    6.87 100.00      11.2
0.2    0.972    1.052    0.399   0.829*  -0.111
          2.42   2.37  10596   1532    6.92 100.00      10.2
0.2    1.095    1.184    0.447   0.844*  -0.083
          2.37   2.32  10577   1535    6.89 100.00       8.9
0.2    1.259    1.361    0.514   0.825*  -0.082
          2.32   2.28  10217   1513    6.75 100.00       7.8
0.2    1.421    1.540    0.587   0.725*  -0.056
          2.28   2.24   9702   1521    6.38 100.00       6.4
0.1    1.683    1.834    0.721   0.600*  -0.001
          2.24   2.20   9551   1538    6.21 100.00       6.1
0.1    1.895    2.071    0.826   0.603*  -0.041
        118.64   2.20 203575  30663    6.64  99.99     142.0
3.3    0.222    0.241    0.093   0.989*  -0.265



Does anyone have any insight into where PAIREF is getting hung up?
I am welcome to any other suggestions with regards to handling this
dataset to determine resolution cutoff.  I can also supply any
other log files that may be useful

Matt

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