Hi Jennifer,
clear drops can still be brought to supersaturation by:
-transfer to wells with lower vapour pressure: exchange or add LiCl or other
concentrated salt solutions in the reservoir
-temperature gradient: place trays on ice/cold surface while hanging drops are
at higher temperature, this will draw more water out of the drops.
-transient supersaturation might be sufficient to trigger nucleation and
subsequent crystal growth: slightly open wells for a few minutes (or longer)
and close again.
-protein solubility also can strongly depend on temperature: move to 4°C etc.
... and why not using the 100mg/ml stock or concentrate even more?
Good luck,
Clemens
Quoting Jens-Christian Navarro Poulsen <[log in to unmask]>:
> Hi Jennifer
>
>
>
> I just want to draw your attention the following paper regarding methylation
> of Lysines, which reduces the solubility of their test proteins.
>
>
>
> Walter
> <http://www.ncbi.nlm.nih.gov/pubmed/17098187?ordinalpos=7&itool=EntrezSystem
> 2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum> TS, Meier C,
> Assenberg R, Au KF, Ren J, Verma A, Nettleship JE, Owens RJ, Stuart DI,
> Grimes JM.
>
>
> <http://www.ncbi.nlm.nih.gov/pubmed/17098187?ordinalpos=7&itool=EntrezSystem
> 2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum> Abstract
>
> Lysine methylation as a routine rescue strategy for protein crystallization.
>
> Structure. 2006 Nov;14(11):1617-22.
>
> PMID: 17098187 [PubMed - indexed for MEDLINE]
>
>
>
> Best regards,
>
>
>
> Jens-Christian Navarro Poulsen
>
> Dept of Chemistry, KU
>
>
>
>
>
> _____
>
> From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of
> Jennifer Han-Chun Tsai
> Sent: 13. maj 2008 18:17
> To: [log in to unmask]
> Subject: [ccp4bb] problem of crystallization
>
>
>
> Hi,
>
>
>
> This topic is not related to CCP4. I am having problem of crystallizing
> one protein. It's a pretty small protein with size around 15kDa. I have
> stock concentration around 100mg/mL. Crystallization plates I set up are
> with concentration of 10mg/mL, 30mg/mL and 50mg/mL. All the plates had been
> set up at least one week. Only around 5 wells per plate or less formed
> precipitation. The rest of wells are pretty clear still. Is there any
> suggestion for reducing protein solubility or increasing the chance of
> getting crystals?
>
>
>
> Thanks for your time,
>
> Jennifer
>
>
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