Problems with thin protein crystals

Stefan Blickling blicklin at made.biochem.mpg.de
Tue Feb 25 06:16:01 EST 1997


> 	We have been able to get thin (>0.05 mm) crystals that grow
> relatively well in the other two dimensions, but this results in weak
> diffraction patterns (~5000 s exposure per frame). Coventional seeding
> techniques fail. Could anyone provide suggestions and ideas on how I could
> grow thicker crystals?
> 	In addition, the diffraction pattern across the top and bottom of 
>  the frame have reflections that are badly split (more like smears), 
> while those across the middle are round. Can anyone suggest a way to 
> reject the poor areas of the frame so that we could extract the good 
> data? We use mainly denzo and scalepack but mosflm and ccp4 are also 
> available.
> 
> Many thanks,
> Steffen
> 

The splitting of the reflections may be due to a bending or shattering
 of the crystal in the cappilary as it sticks to the rounded surface.
Either use a flattened cappilary or one with a greater diameter.

Good luck,

Stefan






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