Re: [ccp4bb]: question in MAD data collection

[Mischa Machius]

Probably the most common reason for misbehavior during scaling of different batches in trigonal space groups is due to the fact that there are two equivalent ways of indexing the lattice. You must make sure that all batches of data are indexed in the same way by making sure that the missetting angles are the same. Hope that helps. Cheers - MM On Dec 1, 2005, at 10:55 AM, Yuequan Shen wrote: Hello, everyone, I got one weird thing happened during my last MAD data collection. There are total 52 Se sites in the one asymmetric unit of my crystal. The space group is P65. After collected 180 degree data set at the Se peak wavelength, I noticed significant decay (from 2.6A to 4.0) during the inverse beam data collection. I stopped the inverse beam data collection after collecting 90 degree data. And then I collect another 180 degree data set using the inverse beam after moving to the another spot of the crystal. I used the same strategy to collect data sets at inflection wavelength and remote wavelength using the same crystal.  The problem occur during the data process. I had no any problem to scale the inf and rem data sets. However, I can not scale the peak data sets together (Rmerge =45% in every shell) collected from two different spots of the same crystal but no any problem to scale them separately (Rmerge=6.0% in total for each one). I tried other crystals and found the same thing. The cc value in SOLVE program between different wavelengths is 0.1 for peak vs inf or rem and 0.8 for inf vs rem. The SOLVE refuse to find any solution (" --No solutions found...quitting "  ). . I am wondering if you guys have the similar experience.    any suggestion and comments are welcome! yuequan the university of chicago This email is intended only for the use of the individual or entity to which it is addressed and may contain information that is privileged and confidential. If the reader of this email message is not the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is prohibited. If you have received this email in error, please notify the sender and destroy/delete all copies of the transmittal. Thank you. -------------------------------------------------------------------------------- Mischa Machius, PhD Assistant Professor UT Southwestern Medical Center at Dallas 5323 Harry Hines Blvd.; ND10.214A Dallas, TX 75390-8816; U.S.A. Tel: +1 214 645 6381 Fax: +1 214 645 6353