Is there a model available? How much of it is built/homologous? You should try indexing it with labelit (try several images) and see if P222 is still the proper point group. See http://cci.lbl.gov/~phzwart/p222.png for subgroups under p222. You may need to consider the lower P2 space groups for this problem. FR On Oct 16, 2009, at 1:20 PM, Laurie Betts wrote:

Hi - We have a data set that seems to process well in primitive orthorhombic. a=80, b=87, c=114. The data has overall Rsymm around 10% to 2.6 Angstrom, where I/sigI > 2, and Chi-squared is around 1.4. Phenix.xtriage shows some pathology in intensity statistics such that the L-test indicates <|L|> = 0.414 and = 0.241, with the L-test Z score = 7.334. The Wilson ratio for acentric refls is 1.774. According the xtriage, There were no "pseudomerohedral" twin laws found, and the comments at the end say "As there are no twin laws possible given the crystal symmetry, there could be a number of reasons......"

Is it more likely that this is a case of pseudo-symmetry, or would one not expect the intensity statistics to have the values they do in that case.

Also, is the absence of twin laws defined by the fact that proper merohedral twinning is not possible for P222 space groups?

Still confused,

Laurie Betts _______________________________________________ phenixbb mailing list [email protected] http://www.phenix-online.org/mailman/listinfo/phenixbb

--------------------------------------------- Francis Reyes M.Sc. 215 UCB University of Colorado at Boulder gpg --keyserver pgp.mit.edu --recv-keys 67BA8D5D 8AE2 F2F4 90F7 9640 28BC 686F 78FD 6669 67BA 8D5D