Thanks for the assistance, everyone. For those who suggested XDS: I forgot to mention that I have tried Mosfim, which is also better than spot fitting than HKL2000. How does XDS compare to Mosflm in this regard?
I am not refining the high R-factor structure with NCS options. Also, my unit cell dimensions are 41.74 A, 69.27 A, and 83.56 A, so there isn't one particularly long axis. I'm guessing the low completeness of the 1.65 angstrom dataset has to do with obstacles the processing software encountered on a sizable wedge of frames (there were swaths of in red in HKL2000). I'm not sure why this dataset in particular was less complete than the others. Thanks, Chris On Fri, Feb 21, 2014 at 6:41 PM, Chris Fage <cdf...@gmail.com> wrote: > Dear CCP4BB Users, > > I recently collected a number of datasets from plate-shaped crystals > that diffracted to 1.9-2.0 angstroms and yielded very nice electron > density maps. There is no major density unaccounted for by the model; > however, I am unable to decrease Rwork and Rfree beyond ~0.25 and > ~0.30, respectively. Probably due to the more 2-dimensional nature of > my crystals, there is a range of phi angles in which the reflections > are smeared, and I am wondering if the problem lies therein. > > I would be grateful if anyone could provide advice for improving my > refinement statistics, as I was under the impression that the > R-factors should be ~5% lower for the given resolution. > > A few more pieces of information: > -Space group = P21, with 2 monomers per asymmetric unit; > -Chi square = 1.0-1.5; > -Rmerge = 0.10-0.15; > -Data were processed in HKL2000 and refined in Refmac5 and/or > phenix.refine; > -PHENIX Xtriage does not detect twinning, but hints at possible weak > translational pseudosymmetry; > -I was previously able to grow one atypically thick crystal which > diffracted to 1.65 angstroms with Rwork/Rfree at 0.18/0.22. > Unfortunately, the completeness of the dataset was only ~90%. > > Regards, > Chris >
