Dear Jacob, dear TO,
(I have wondered what can be 'micro' about diffraction - would you know?)
it would be very exciting to get the structure by electron diffraction - as
much as I know it would be the first new structure solved from a 3D crystal
with electron radiation in the PDB. You would have to contact one of the 3-4
labs that to electron diffraction of protein samples (Abrahams, Gonen,
Hovmoeller / Zou (possibly), and Yonekura/Toyoshima in alphabetic order). The
first and the last group are equipped with sensitive hybrid pixel detectors
that might help.
A good test to get an idea about the resolution you might get from electron
diffraction is to scratch up as many of your crystals and analyse the powder
pattern with a strong X-ray source (synchrotron, or very good home source).
Note that when you can see the crystals with a light microscope, they are most
likely too big for electron diffraction - you might end up seeing a black
screen with no electron penetrating your samples.
Best regards,
Tim
On Wednesday, March 1, 2017 1:59:44 PM CET Keller, Jacob wrote:
> Although trying to refine the crystals is perhaps the most straightforward
> thing, you might consider trying micro electron diffraction (micro-ED) with
> the existing samples—the technique is working increasingly better, and
> would work well with your tiny crystals. Look at Tamir Gonen’s recent
> papers for more info.
> All the best,
>
> Jacob Keller
>
> From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of ???
> Sent: Wednesday, March 01, 2017 3:53 AM
> To: [log in to unmask]
> Subject: [ccp4bb] How to refine this needle crystal of membrane complex?
>
> Dear all,
> I am trying to obtain crystals of membrane complex. Now, I have obtained the
> complex with appropriate stoichiometry after a series of purification in
> DDM, then I get extremely thin needles (as shown in figure) in some
> conditions such as 28% MPD, 0.1 M NaAc pH 4.5 or 45% MPD,0.1 M Bis-Tris pH
> 6.5, 0.2 M CaCl2. However, there are not any improvements through changing
> the concentration of precipitants/salts or adding the additives/detergents
> to the protein.
> I would be very happy if anybody could give me some advice about this
> crystal refinement.
> With best regards.
>
>
> [cid:image001.png@01D2926A.28CB0C70]
--
--
Paul Scherrer Institut
Tim Gruene
- persoenlich -
OFLC/104
CH-5232 Villigen PSI
phone: +41 (0)56 310 5297
GPG Key ID = A46BEE1A
|