Give XDS a try with your data or d*trek with 3d profile fitting. Did you try iMosflm or the old Mosflm ? If old, then POSTREF WIDTH 15 might help and POSTREF FIX BEAM You saw the nice packing from Tjaard, if all your molecules have contact with each other than that's fine I was just concerned about molecules in space without contact, then you are missing something. Still reprocessing the data (sorry Wladek) might squeeze out a bit more of your existing data. In particular if you use NCS averaging with those weak highres reflections you might get better side chain density. Jürgen On Dec 14, 2011, at 11:41 AM, Stefan Gajewski wrote: Jürgen, Have you checked a simple selfrotation function in your currently favored space group ? Yes, both selfrotation function and patterson map do not look suspicious in I422. Do you have sufficient data collected to start out in P1 or C2 ? Then I would start there and systematically look at selfrotation functions in those space groups. Also check the native Patterson for translational NCS. I got ~220 degrees before the radiation damage became significant, so there should be enough data and I will look into it. 4 A is not great for stable refinement of cell parameters, which program did you use and which parameters did you fix? HKL2000 without fixing parameters. mosflm can't hold on the lattice and I haven't tried d*trek, yet. Did you use main.ncs=true in the SA approach ? yes Pointless or xtriage ? xtriage Why does it take a year to grow those crystals ? Well, other crystals don't diffract and the protein is quite stable in solution. That's how it is, I guess? Out of curiosity, how did you collect on this crystal without overlapping reflections ? I got away with 1 second exposure and 0.75 degree oscillation at 650mm detector distance. there are some predicted overlaps but they are in those regions that are empty due to anisotropy. Our cryo condition gives well separated small spots of nice, round shape, mosaicity is ~0.6. The pattern itself looks great, although the beamstop shadow is quite big on the frames. Thank You, Stefan ...................... Jürgen Bosch Johns Hopkins University Bloomberg School of Public Health Department of Biochemistry & Molecular Biology Johns Hopkins Malaria Research Institute 615 North Wolfe Street, W8708 Baltimore, MD 21205 Office: +1-410-614-4742 Lab: +1-410-614-4894 Fax: +1-410-955-2926 http://web.mac.com/bosch_lab/