"Useable" anomalous signal depends on what you want to use it for...
If it is to generate experimental phases, then the SHELXC/D/E criteria of Dano/SigDano are pretty good. If you already know the structure and want to check if there is Br there then a much weaker signal can answer the question. You need to do a anomalous difference map and search for peaks.. Steps are: Run refmac to generate output file with h k l F SIGF ... PHIC .. FOM.. Run cad to merge refmac output with the DANO SIGDANO columns generated by Ctruncate after data processing runn fft with the "anomalous map" option and a peak search. Inputs DANO SIDANO PHIC FOM ( fft automatically advances PHIC by 90 degrees ) (Yes - it SHOULD be automated!! ) Read the peak search into coot Check whether the sites show up likely anomalous scatterers - eg Br, S, Ca etc.. This often works Eleanor On 4 September 2014 22:47, Boaz Shaanan <[email protected]> wrote: > Also, if you process your data using XDS, it'll give you good indication > for the strength of the anomalous signal. I find the XDS and Aimless > indications to agree quite well. > > Boaz > > > > > > > > > > > > *Boaz Shaanan, Ph.D. Dept. of Life > Sciences Ben-Gurion University of the > Negev Beer-Sheva > 84105 > Israel > E-mail: > [email protected] <[email protected]> Phone: 972-8-647-2220 Skype: > boaz.shaanan Fax: 972-8-647-2992 or 972-8-646-1710 * > > > > > > ------------------------------ > *From:* CCP4 bulletin board [[email protected]] on behalf of CPMAS > Chen [[email protected]] > *Sent:* Thursday, September 04, 2014 11:05 PM > *To:* [email protected] > *Subject:* [ccp4bb] Reliable criteria to tell Anomalous or not? > > Dear All CCP4 users, > > Recently, I have protein crystals cocrytallized with Br-containing > ligand. sometimes, I feel confusion about whether the data have reliable > anomalous information or not. > > Do you guys have some recommendation of the criteria? phenix reported > anomalous measurability, CCP4/aimless has RCRanom. Sometimes, they are not > consistent. > > Thanks! > > Charles > > -- > > *************************************************** > > Charles Chen > > Research Associate > > University of Pittsburgh School of Medicine > > Department of Anesthesiology > > ****************************************************** > >
