Another reason for the smearing (apart from being an intrinsic property of your crystals, or being caused by cryo-protection) may be that your crystals are sensitive to handling.
Trying in-plate room temperature diffraction might show you if that is the case. If it diffracts well in-plate, you’d have to experiment with different handling techniques to retain that diffraction.
Do the crystals move around a lot while “fishing”? If so, covering the drop with oil and looping them out through the oil might help (or it might make things worse…).
I don’t think phase separation is bad for the crystal, whatever it takes to get a crystal is valid! However, the phase separation does mean it is difficult to know what the conditions directly surrounding the crystal are, making design of suitable harvesting buffers/cryo solution very difficult. You may have to try different solutions until you get the right one (preferably by analysing diffraction quality of each, because inspection of the crystal by eye for degradation/cracking may not be enough). Again, a room temperature, and even better in-plate, diffraction pattern would give you a good base-line to work towards.
Mark J van Raaij
Dpto de Estructura de Macromoleculas
Centro Nacional de Biotecnologia - CSIC
c/Darwin 3
E-28049 Madrid, Spain
tel. (+34) 91 585 4616
http://wwwuser.cnb.csic.es/~mjvanraaij
> On 25 Jul 2016, at 10:13, 张士军 <[log in to unmask]> wrote:
>
> AND my complex crystal is also grown in condition of MPD ,the diffraction result is smearing too .How to explain this ?
> 在2016-07-25 16:10:59，张士军[log in to unmask]写道：
>
> Another situation of my crystal drop is that the sodium citrate salt is not immiscible with the MPD,that is mean the crystal is grown in a phase separation drop .i wonder that does the phase separation bad to the crystal ?
> Thanks
> Shijun
> 在2016-07-25 15:53:35，张士军[log in to unmask]写道：
>
> I would definitively try a shot at room temp. The smearing might be a property of your crystals, not of the freezing.
>
> If the room temperature pictures look good, you could consider collecting a room temp data set using multiple crystals or work on your freezing conditions.
>
> If the room temperature pictures are smeared as well, you have to work on the crystallization conditions (additives etc.) or try to process the smeared data set (if the smearing is not too bad).
>
>
>
> Good luck!
>
> Herman
>
>
>
> Von: CCP4 bulletin board [mailto:[log in to unmask]] Im Auftrag von ???
> Gesendet: Montag, 25. Juli 2016 04:35
> An: [log in to unmask]
> Betreff: Re: [ccp4bb] cyrobuffer
>
>
>
> yes ,i had try both small and big crystals ,and they were same situation ,and i freeze in the LN2.does that mean my crystals are not suit in freeze circumstance ,can i try RM diffraction ?
>
> 在2016-07-25 08:30:40，张士军[log in to unmask]写道：
>
> How big are your crystals? Try small er ones if you used huge ones.
>
> 50%MPD freezes clear in my hands.
>
> Do you freeze in the stream or LN2?
>
> Jürgen
>
> ......................
> Jürgen Bosch
> Johns Hopkins University
> Bloomberg School of Public Health
> Department of Biochemistry & Molecular Biology
> Johns Hopkins Malaria Research Institute
> 615 North Wolfe Street, W8708
> Baltimore, MD 21205
> Office: +1-410-614-4742
> Lab: +1-410-614-4894
> Fax: +1-410-955-2926
> http://lupo.jhsph.edu
>
>
>
> On Jul 24, 2016, at 8:11 PM, 张士军 <[log in to unmask]> wrote:
>
>
>
> Hi all
>
> I have a crystal grown in 50%MPD 0.2M sodium citrate pH7.2 ,because MPD can be a cyrobuffer ,so I harvested them directly .But the spots are smearing when I difftacted it .then I add 5%glycerol in the cyrobuffer when harvested it ,the result is the same .Can anyoone give me some suggestion about this situation .Thanks a lot !!!!!
>
> ShijunZhang
>
> School of Life Science
>
> Xiamen University
>
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