Vicky, streak seeding is a very good method, but it can be quite a lot of work. Before he tries that, why wouldn't we suggest to Liuqing that he should try MMS - that is, adding a liquid seed stock to random screens? That way he is likely to end up with seeds in wells with similar conditions that happen to be in the metastable zone of the phase diagram, and also with seeds in *completely unrelated conditions *that are also in the metastable zone. That way you can cast your net very wide.
One simple experiment does so much - it is also an additive experiment : ) Part of the art of crystallization is to try lots of things without thinking too much. Patrick On 12 July 2017 at 07:50, Vicky Tsirkone <vtsirk...@gmail.com> 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> 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> 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> 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 Douglas Instruments Ltd. >>> Douglas House, East Garston, Hungerford, Berkshire, RG17 7HD, UK >>> Directors: Peter Baldock, Patrick Shaw Stewart >>> >>> http://www.douglas.co.uk >>> Tel: 44 (0) 148-864-9090 <01488%20649090> US toll-free >>> 1-877-225-2034 <%28877%29%20225-2034> >>> Regd. England 2177994, VAT Reg. GB 480 7371 36 >>> >> >> >> > -- 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 Tel: 44 (0) 148-864-9090 US toll-free 1-877-225-2034 Regd. England 2177994, VAT Reg. GB 480 7371 36
