Hi, I have a diffraction data-set from a hexagonal rod shaped crystal, to about 2.0 Å. The problem comes when I try to process the data - Mosflm won't index it, and XDS indexes it as P622, but the unit cell is too small to contain even a single molecule of my protein. I have tried integrating it in some different space groups that XDS suggested (P2, C2, P1) but in all cases the Rmerge and Rmeas are worse than for P622.
If I scale in P622 (or any of the other space groups) I get odd results from the twinning tests. For example, the 4th moment of E (expected values of 2 for untwinned, 1.5 for perfect twin) is around 1.1, and the L-test and cumulative intensity distribution are unusual as well (uploaded images here: http://tinypic.com/r/65rfr7/7 and here: http://tinypic.com/r/30adgyr/7 ) Has anyone else had similar issues? Any ideas would be appreciated. Thanks, Jason. -- Jason Busby PhD Student Laboratory of Structural Biology School of Biological Sciences University of Auckland Thomas Building 110 3a Symonds St Private Bag 92019 Auckland 1142 New Zealand ph: +64 9 3737599 ext 83888 fx: +64 9 3737414
