I'm not clear what is the reasoning here behind using a low res cutoff for the SRF (i.e. lower than the data limit). It seems to me that using all valid data available can only increase the signal/noise ratio, and omitting good data can only have a deleterious effect (as will any kind of data incompleteness - this is well-documented).
I can certainly see the argument for applying a high resolution cutoff because of data quality: personally I use a 40% limit in Rmerge and 1.5 in <I/sig(I)> for the outer shell, but I don't want to get into an argument about the exact figures: as long as you have some kind of filtering of poorly measured data. Then of course there may be a limitation imposed by the software, i.e. the high res limit depends on the radius of integration, though in practice I doubt that's going to be a real limitation (e.g. for 2 Ang data you are limited to a 35 Ang radius in Polarrfn). Other than those limitations what's the purpose or advantage of a high res cutoff? Note that the situation for a SRF is quite different to that for a XRF, because in that case there will be a limitation imposed by the RMSD of your model from the true structure. Cheers -- Ian > 1) Your dataset has a high overall Rmerge. The outmost shell (70%) > is very high, which suggests a need to shrink resolution. What about > I/s(I), redundancy and completeness? Also, how many reflections > (percentage) have been subjected to rejection? Too many rejections may > mean a SG error. > > > 70% Rmerge alone in the outer shell, can indeed be reasonable for such > high symmetry, depending on e.g. redundancy and what Lijun also mentions. > I would be more interested in the low resolution Rmerge to be able to have > an opinion about the dataset ... > > > > 2) Software analyses including Phenix.xtriage give good suggestions, > but they should be used reasonably. P6n22 could be twinned from P6n or > P3n12 or P3n21 or even P3n, when close to be perfectly twinned. > > > 5) Use a lower resolution ~4-5 Å data to do a better self rotation > function. Why do not paste a .ps plot for the SR peaks. > > > Using low resolution for SF is a good idea, 5-6 is also nice. But please > do not send us any attachments at the BB ;-) Disclaimer This communication is confidential and may contain privileged information intended solely for the named addressee(s). It may not be used or disclosed except for the purpose for which it has been sent. If you are not the intended recipient you must not review, use, disclose, copy, distribute or take any action in reliance upon it. If you have received this communication in error, please notify Astex Therapeutics Ltd by emailing i.tic...@astex-therapeutics.com and destroy all copies of the message and any attached documents. Astex Therapeutics Ltd monitors, controls and protects all its messaging traffic in compliance with its corporate email policy. The Company accepts no liability or responsibility for any onward transmission or use of emails and attachments having left the Astex Therapeutics domain. Unless expressly stated, opinions in this message are those of the individual sender and not of Astex Therapeutics Ltd. The recipient should check this email and any attachments for the presence of computer viruses. Astex Therapeutics Ltd accepts no liability for damage caused by any virus transmitted by this email. E-mail is susceptible to data corruption, interception, unauthorized amendment, and tampering, Astex Therapeutics Ltd only send and receive e-mails on the basis that the Company is not liable for any such alteration or any consequences thereof. Astex Therapeutics Ltd., Registered in England at 436 Cambridge Science Park, Cambridge CB4 0QA under number 3751674
