We had a complex many years ago that could sometimes be convinced to crystallize by poking the drops (probably with a hair): if I remember correctly, both poking some of the skin into the drop and pulling some of the oily goo into more contact with the aqueous phase. Then again, that complex also sometimes crystallized without help, so it might not be the best example for your case.
My group has generally found that the most important variable is the ends of the DNA, and often when we get the "winner" DNA we get at least crappy microcrystals under a variety of conditions. Hope you get nice fat crystals soon! Phoebe ________________________________ From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Johannes Cramer [johannes.cra...@gmail.com] Sent: Friday, April 07, 2017 7:37 AM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] suggestion on protein crystallization optimization from phase separation Dear Joseph, You have probably already done so, but have you tried in- or decreasing your protein+DNA concentration? I had a similar problem with proteins that were concentrated too low. I had to increase protein and decrease Ammonium sulfate (precipitant in my case) concentration. Cheers, Johannes 2017-04-06 17:16 GMT+02:00 Joseph Ho <sbddintai...@gmail.com<mailto:sbddintai...@gmail.com>>: 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
