MMS (microseed matrix screening) into several screens, as Patrick suggested earlier, would be the first choice for me. Works very often.
Good luck! Olga > On 12 Jul 2017, at 08:48, Frank von Delft <frank.vonde...@sgc.ox.ac.uk> wrote: > > The point I was failing to make: reducing either protein or precipitant > concentration will indeed reduce nucleation, but often won't get you bigger > or more single crystals: it will just make the appearance of crystals less > reliable. > The way to get big single reliable crystals is to increase protein and > greatly reduce precipitant. > (Even better: do seeding. Like Vicky said. Incredible how often people > don't bother to do seeding, yet it solves so many problems.) > > phx > > On 12/07/2017 07:50, Vicky Tsirkone wrote: >> Dear Frank, >> >> I may see in the attached pic several nucleation points and a considerable >> amount of microcrystals. Based to my knowledge decreasing the concentration >> of the precipitant and/or the protein concentration would be a reasonable >> approach to refine the initial hits. >> By checking the diagram as you correctly mentioned you may see that the fine >> tuning of protein and precipitant concetration may lead to the desirable >> result without reaching the precipitation zone. >> >> Patrick just check your screens. Just a rule of thumb, if you see >> precipitation in the ~60% of your drops then you should definitely reduce >> the protein concentration. >> >> ps dont forget to try the streak seeding, as well. >> >> Have a nice day and again good luck. >> >> Vicky >> >> On Wed, Jul 12, 2017 at 8:50 AM, Frank von Delft >> <frank.vonde...@sgc.ox.ac.uk <mailto:frank.vonde...@sgc.ox.ac.uk>> wrote: >> Actually, you should try increasing the protein concentration - a lot. But >> be prepared to drop the precipitant concentration to almost nothing (1 or 2% >> isn't "low"). >> To understand why, look at the phase diagram and what we assume about vapour >> diffusion. (Which I'm assuming is what you're doing.) >> >> On 12/07/2017 06:28, Vicky Tsirkone wrote: >>> Dear Patrick, >>> >>> You may reduce the protein concentation, as well. >>> Another option could be the streak seeding by exploiting the drop of your >>> initial condition. >>> >>> Good luck, >>> >>> V.T. >>> >>> On Mon, Jul 10, 2017 at 7:17 PM, Patrick Shaw Stewart >>> <patr...@douglas.co.uk <mailto:patr...@douglas.co.uk>> wrote: >>> >>> Microseed them into two or three random screens. >>> >>> Search for MMS and rMMS online. >>> >>> Good luck >>> >>> Patrick >>> >>> >>> >>> >>> On 10 July 2017 at 15:47, Liuqing Chen <519198...@163.com >>> <mailto:519198...@163.com>> wrote: >>> hello everyone! >>> I get a condition (10% w/v PEG 6000, 100mm HEPES PH7.0) in which my protein >>> grow small needle like crystals, how can i optimize it to get bigger >>> crystals? the attach is the crystals figure. >>> thanks in advance >>> sincerely >>> Liuqing Chen >>> >>> >>> >>> -- >>> patr...@douglas.co.uk <mailto:patr...@douglas.co.uk> Douglas >>> Instruments Ltd. >>> Douglas House, East Garston, Hungerford, Berkshire, RG17 7HD, UK >>> Directors: Peter Baldock, Patrick Shaw Stewart >>> >>> http://www.douglas.co.uk <http://www.douglas.co.uk/> >>> Tel: 44 (0) 148-864-9090 US toll-free 1-877-225-2034 >>> <tel:%28877%29%20225-2034> >>> Regd. England 2177994, VAT Reg. GB 480 7371 36 >>> >> >> >
