Kay,Thank you for your explanation. The radiation damage was not the factor, but there was something strange about this crystal (actually two crystals had the same strange behavior). I could not process them in HKL2000, but it showed the problem (see pictures in the attachment). The processing in XDS was done at the CLS (Canadian Light Source). I know they always have the latest version of XDS.
Maia Kay Diederichs wrote:
Maia,provided radiation damage is not a major detrimental factor, your data are just fine, and useful also in the high resolution shell (which still has <I/sigma> of 2.84 so you could probably process a bit beyond 2.25A).There is nothing wrong with R_meas of 147.1% since, as others have said, R_meas is not limited to 59% (or similar) as a refinement R-factor is. Rather, R_meas is computed from a formula that has a denominator which in the asymptotic limit (noise) approaches zero - because there will be (almost) as many negative observations as positive ones! (The numerator however does not go to zero)Concerning radiation damage: First, take a look at your frames - but make sure you have the same crystal orientation, as anisotropy may mask radiation damage! Then, you can check (using CCP4's loggraph) the R_d plot provided by XDSSTAT (for a single dataset; works best for high-symmetry spacegroups), and you should also check ISa (printed in CORRECT.LP and XSCALE.LP).HTH, KayP.S. I see one potential problem: "XSCALE (VERSION December 6, 2007)" when the calculation was done 28-Aug-2009. There were quite a number of improvements in XDS/XSCALE since that version. The reason may be that a licensed, non-expiring version was used - make sure you always rather use the latest version available!> -------- Original Message -------- > Subject: [Fwd: Re: [ccp4bb] I/sigmaI of >3.0 rule] > Date: Thu, 3 Mar 2011 10:45:03 -0700 > From: Maia Cherney <ch...@ualberta.ca> > > > > -------- Original Message -------- > Subject: Re: [ccp4bb] I/sigmaI of >3.0 rule > Date: Thu, 03 Mar 2011 10:43:23 -0700 > From: Maia Cherney <ch...@ualberta.ca> > To: Oganesyan, Vaheh <oganesy...@medimmune.com> > References: <2ba9ce2f-c299-4ca9-a36a-99065d1b3...@unipd.it> > <4d6faed8.7040...@ualberta.ca> > <021001cbd9bc$f0ecc940$d2c65bc0$@gmail.com> > <4d6fcab6.3090...@ualberta.ca> <4d6fcbff.2010...@ualberta.ca> > <73e543de77290c409c9bed6fa4ca34bb0173a...@md1ev002.medimmune.com> > > > > Vaheh, > > The problem was with Rmerg. As you can see at I/sigma=2.84, the Rmerge > (R-factor) was 143%. I am asking this question because B. Rupp wrote > "However, there is a simple relation between <I/sigI> and R-merge > (provided no other indecency has been done to the data). It simply is > (BMC) Rm=0.8/<I/sigI>." > Maybe my data are indecent? This is the whole LP file. > > Maia > > MMC741_scale-2.25.LP > >>******************************************************************************> XSCALE (VERSION December 6, 2007) 28-Aug-2009>******************************************************************************> > Author: Wolfgang Kabsch > Copy licensed until (unlimited) to > Canadian Light Source, Saskatoon, Canada. > No redistribution. >
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