Dear Francesco,
A few remarks from my side: I would call the resolution of this data set 1.7 Å and not 1.56 Å, but this is a matter of taste. The first thing that struck me with this data is that the low resolution bin (8.4 - 22.84 Å) has a rather poor Rmeas. Also the aimless logfile seems to suggest that you data suffers from ice rings. Although I am a great fan of XDS, I find that XDS handles ice rings quite poorly. In my hands, these ice-riddled data sets produce exactly the symptoms you describe: high (free) R-factors for no apparent reason.
In this case I would try the following:
-rigorously cut out the ice rings from your data, as is suggested in the XDS manuals
-do some refinement with the Mosflm-processed and look what kind of R-factors you then get.
Also you have a very high redundancy. If your crystal suffered significant radiation damage, I would cut out the frames where the crystal starts deteriorating. You probably still get very complete data, potentially of better quality.
Of course, you could also try to improve your cryo-buffer and try to collect ice-free data!
Best,
Herman
-----Ursprüngliche Nachricht-----
Von: CCP4 bulletin board [mailto:[log in to unmask]] Im Auftrag von Francesco Papi
Gesendet: Montag, 22. August 2016 13:47
An: [log in to unmask]
Betreff: Re: [ccp4bb] Rfree stuck around 32%
Dear Mohamed,
Thank you for your suggestion. First of all, I have to say that I have worked on XDS-processed (merged) data, but now XDS is not available to me (the computer on which the program was installed crushed during the summer holidays and I have only a windows laptop...). I am sending you the Aimless output of Mosflm-processed data. I have pasted the results below and the log file here is attached.
Thank you
Francesco Papi
Summary data for Project: New Crystal: New Dataset: New
Overall InnerShell OuterShell
Low resolution limit 22.84 22.84 1.59
High resolution limit 1.56 8.40 1.56
Rmerge (within I+/I-) 0.117 0.103 1.445
Rmerge (all I+ and I-) 0.119 0.104 1.481
Rmeas (within I+/I-) 0.123 0.108 1.528
Rmeas (all I+ & I-) 0.122 0.108 1.528
Rpim (within I+/I-) 0.036 0.029 0.481
Rpim (all I+ & I-) 0.029 0.024 0.356
Rmerge in top intensity bin 0.100 - -
Total number of observations 144739 1378 6825
Total number unique 8898 79 439
Mean((I)/sd(I)) 11.2 24.3 1.2
Mn(I) half-set correlation CC(1/2) 0.995 0.997 0.847
Completeness 99.2 96.2 96.8
Multiplicity 16.3 17.4 15.5
Anomalous completeness 97.4 100.0 87.5
Anomalous multiplicity 8.8 14.3 9.0
DelAnom correlation between half-sets -0.050 0.474 0.004
Mid-Slope of Anom Normal Probability 0.746 - -
Estimates of resolution limits: overall
from half-dataset correlation CC(1/2) > 0.50: limit = 1.56A == maximum resolution
from Mn(I/sd) > 2.00: limit = 1.61A
Estimates of resolution limits in reciprocal lattice directions:
Along h k plane
from half-dataset correlation CC(1/2) > 0.50: limit = 1.71A
from Mn(I/sd) > 2.00: limit = 1.84A
Along l axis
from half-dataset correlation CC(1/2) > 0.50: limit = 1.56A == maximum resolution
from Mn(I/sd) > 2.00: limit = 1.56A ==
maximum resolution
Anisotropic deltaB (i.e. range of principal components), A^2: 13.66
Average unit cell: 41.25 41.25 68.51 90.00 90.00 90.00
Space group: P 41 21 2
Average mosaicity: 1.14
Minimum and maximum SD correction factors: Fulls 0.00 0.00 Partials
1.71 900.76
The anomalous signal appears to be weak so anomalous flag was left OFF
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