Jim Pflugrath and a couple of high school interns shot a short video on halide quick soaks a few years back. You can find it at https://www.youtube.com/watch?v=45Qc3jOPaKY.
Cheers, Joseph D. Ferrara, Ph.D. CSO Deputy Director, X-ray Research Laboratory Vice President, American Crystallographic Association Rigaku Corporation 9009 New Trails Drive The Woodlands, TX 77381 Tel: 281-362-2300 x 168 Skype: xrayjoe url: www.rigaku.com From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Roger Rowlett Sent: Tuesday, April 03, 2018 9:57 AM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Sulphur SAD at home source Iodine is ideally suited for Cu K-alpha SAD phasing, and iodide ions can normally be easily added by soaking crystals in potassium iodide containing solutions, which can be done at the time of cryopreservation. A quick lit search will turn up the appropriate protocols. For structural genomics work where MR was unsuccessful or unusable, iodide soaks were found to work as much as 80% of the time. I've used iodide-soaked lysozyme for an XRD teaching lab and undergraduate research student training, and SAD phasing works really well on an overnight data collection on our Oxford Diffraction PX-ultra system. It's worth a shot, and very easy to do. Many proteins will tolerate soaking, especially if crystallized from salts. _______________________________________ Roger S. Rowlett Gordon & Dorothy Kline Professor Emeritus Department of Chemistry Colgate University 13 Oak Drive Hamilton, NY 13346 tel: (315)-228-7245 ofc: (315)-228-7395 fax: (315)-228-7935 email: rrowl...@colgate.edu<mailto:rrowl...@colgate.edu> On 4/3/2018 10:46 AM, Eleanor Dodson wrote: Well - the S f" is only ~ 0.5 at Cu Kalpha so the signal will be very weak.. Very accurate data may get a solution but you first have to position the S atoms... Much easier to try to make a heavy atom derivative! Eleanor On 3 April 2018 at 15:26, Manoj Saxena <00001d16aa30e8a1-dmarc-requ...@jiscmail.ac.uk<mailto:00001d16aa30e8a1-dmarc-requ...@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
