Probably echoing others but if you are looking at these cryogenically, small changes in the cryoprotectant concentration can have a big effect, similarly pH tweaking can help. Your conditions seem to be very similar to a commercial cocktail and a little optimization may go a long way. That said, there is a long way from 8A to something useful and I'd be thinking of possible new constructs or looking at other conditions that produced a lead. Do you have access to SONICC and two photon UV at all? At the crystallization screening center here (http://getacrystal.org) we find this very useful to identify other conditions that initially look like precipitate but that can be successfully optimized into well diffracting crystals.
Best, Eddie Edward Snell Ph.D. Biological Small Angle Scattering Theory and Practice, Eaton E. Lattman, Thomas D. Grant, and Edward H. Snell. Available through all good bookshops, or direct from Oxford University Press President and CEO Hauptman-Woodward Medical Research Institute BioInnovations Chaired Professorship, University at Buffalo, SUNY Director of the NSF BioXFEL Science and Technology Center 700 Ellicott Street, Buffalo, NY 14203-1102 hwi.buffalo.edu Phone: (716) 898 8631 Fax: (716) 898 8660 Skype: eddie.snell Email: esn...@hwi.buffalo.edu Heisenberg was probably here! -----Original Message----- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Liuqing Chen Sent: Monday, June 4, 2018 6:58 AM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] suggestion of crystallization optimization Hello everyone! I get a crystal several months ago, but the crystals diffraction very low resolution (around 8A) or no diffraction. My sample buffer is 20mm Hepes ph7.0, 50mm NaCl, my protein pI is 5. the codition grow crytal is : 30% PEG400, 100mm hepes 7.5, 200mm MgCl2. I also tried additive screen, all the crystals appear the same apparence, even i seeding optimization, have no improve. the attach is my crystals. what should i do next? thanks in advance. sincerely Liuqing chen ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
