Dear Manoj, providing your crystals diffract to at least 2.5 Å and the sulfurs are ordered, you should be able to solve your structure without too many problems. As a first experiment, I would recommend collecting 360 degrees of data. Process these with XDS and the FRIEDEL'S_LAW= FALSE option and see how much anomalous signal CORRECT.LP reports, if you've got stars in the values of the Anomal Corr column, you're on the right track. Try to phase with SHELXD, following the advice on http://shelx.uni-goettingen .de/tutorials.php.
If you don't succeed, you might need higher multiplicity. If you have a kappa or chi goniometer, you can reorient the crystal and collect another 360 degrees and another 360 degrees, and so on. Merge all data in XSCALE until you can solve the structure. I once wrote a little tutorial for doing S-SAD on the home source that you might want to follow. http://www.imperial.ac.uk/x- ray-crystallography/learning-more/sulphur-sad/ With an HPC detector (or even an image plate) you'd getter better data than with a CCD detector and be able to solve your structure quicker. (Disclaimer: I work for a company that makes HPC detectors.) I consider the home source a great place to solve structures by native SAD. All best. Andreas On Tue, Apr 3, 2018 at 4:26 PM, Manoj Saxena <00001d16aa30e8a1-dmarc-reques t...@jiscmail.ac.uk> wrote: > Hi All, > > I am writing to seek advice on doing sulphur SAD data collection > at Cu based home source for a protein that is 12 KDa and has 6 S atoms. > I have seen some links online and some references but would be grateful if > you can share your know-how for success with this. > Like what multiplicity of data would be good to aim for and > data processing tips. > Inputs from people who have tried and failed would also be highly > appreciated. > > Thank you > Manoj Saxena > University of Puerto Rico > > > -- <https://www.dectris.com> Andreas Förster, Ph.D. MX Application Scientist, Scientific Sales Phone: +41 56 500 21 00 <+41%2056%20500%2021%2000> | Direct: +41 56 500 21 76 <+41%2056%20500%2021%2076> | Email: andreas.foers...@dectris.com DECTRIS Ltd. | Taefernweg 1 | 5405 Baden-Daettwil | Switzerland | www.dectris.com [image: LinkedIn] <https://www.linkedin.com/company/5067919> [image: facebook] <https://www.facebook.com/pages/Dectris-Ltd/623855944369304> <https://twitter.com/DECTRIS_News> Confidentiality Note: This message is intended only for the use of the named recipient(s) and may contain confidential and/or privileged information. If you are not the intended recipient, please contact the sender and delete the message. Any unauthorized use of the information contained in this message is prohibited.
