Hi, I just got a MAD dataset (~2.5A) of a crystal that so far seems to belong to P31 or P32 space group and that also scales pretty well in P3121 or P3221. According to the UCLA twinning server, the P31/P32 crystal is merohedrally twinned with a twinning fraction of 0.33 and following a twinning operation h,-h-k,-l. CNS gives a twinning fraction of 0.42.
Although we have solved twinned crystals in the lab with similar twinning fractions/resolution in the past using SOLVE or BnP/SHELX, only realizing that the crystal was twinned during refinement when the R values wouldn't go down. In this P31/P32 case, however, I can't solve the twinned data with any program, or at least I can't get interpretable electron density maps. Any ideas, clues? Is there a way to get a program that will detwin raw intensity data (like *.sca files directly from scalepack)? Thanks, Jordi
