I second the hkl2map/SHELXCDE approach. Two complete examples explaining how to do this for MAD and S-SAD cases are in my book. I wish to emphasize the importance of a) running enough trials b) careful selection of resolution cutoffs c) look at the solution distribution d) play with SHELXE parameters. The hkl2map graphs are enormously helpful for this purpose.
BR -----Original Message----- From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of Tim Gruene Sent: Tuesday, June 29, 2010 2:29 AM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] measure of anamolous signal Dear Murugan, you can use the program hkl2map from Thomas Schneider, available at http://webapps.embl-hamburg.de/hkl2map/ It's a graphical interface to the programs shelx c/d/e which are available from http://shelx.uni-ac.gwdg.de/SHELX/index.html With SAD data you want to look at the d"/sigma line at the end of the shelxc output. Where that drops below about 1.3 is approximately where your anomalous signal ends. You might get slightly improved statistics with xprep instead of shelxc, but xprep is not free and you have to get a copy from Bruker-AXS. Tim On Tue, Jun 29, 2010 at 02:35:29PM +0530, Vandu Murugan wrote: > Dear all, > I have collected a 2.7 angstrom home source data with Cu-Kalpha > source for a protein with 6 cysteines, with a multiplicity of around > 23. I need to know, is there any significant anamolous signal present > in the data set, since there is no good model for my protein. Can any > one tell, which program to run, and what parameter to see? Thanks in advance. > > cheers, > Murugan -- -- Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen GPG Key ID = A46BEE1A
