I would also point out that a key part of the technique described in the reference below is to vary the temperature. The Lenhoff group published a nice study on protein phase behavior where they talk about liquid-liquid phase separation amongst other things. Figure 1 of the paper (Dumetz et al, Biophys J. 94, 570-583, 2008, 10.1529/biophysj.107.116152) can be recast in the conventional phase diagram space and shows how temperature affects the gelation point and can be used to shift the phase.
Cheers, Eddie http://Getacrystal.org Edward Snell Ph.D. President and CEO Hauptman-Woodward Medical Research Institute Assistant Prof. Department of Structural Biology, University at Buffalo 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 [cid:image001.png@01D2B21A.8EA7C860] Heisenberg was probably here! From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Kevin Jude Sent: Monday, April 10, 2017 4:41 PM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] suggestion on protein crystallization optimization from phase separation I had success once by varying the drop volume ratios as described here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203341/ although we ended up getting data from a different crystal form. ~1 M LiSO4 is a surprising condition for cocrystallizing protein and DNA if they aren't covalently or topologically linked. Best of luck to you. kmj On Thu, Apr 6, 2017 at 8:16 AM, Joseph Ho <sbddintai...@gmail.com<mailto:sbddintai...@gmail.com>> wrote: Dear all: I would like to seek your suggestion on protein crystallization from phase separation. We recently observed many small round droplets shown in our protein/DNA crystallization. Condition are 0.8M-1.6M LiSO4; 20mM MgCl2; pH 5-8; protein conc. ~15mg/ml). The UV microscope confirms those are protein-rich phase separation. We have tried to change conc. of LiSO4 and pH. Still we got different size and amount of small round droplets. At 20 degree, those droplets appear within one day and at 4 degree, it takes two-three days. We also tried additive and silver bullet screen. So far, we have not found a condition to have protein crystals. The protein is already truncated. Several DNA constructs are on-going. At this point, I would like to seek your advice on the method to optimize the condition. Based on PS. Any people have luck with protein crystallization by streaking the Gelationous protein to new drop as shown in http://xray.bmc.uu.se/terese/tutorial3.html . Can you please share your experience with us? Thanks for your help. Joseph Ho -- Kevin Jude, PhD Research Specialist, Garcia Lab Departments of Molecular & Cellular Physiology and Structural Biology Stanford University School of Medicine Beckman B177, 279 Campus Drive, Stanford CA 94305 Phone: (650) 723-6431<tel:%28650%29%20723-6431>
