Dear Lisa
It is not uncommon to see breakdown products when you run crystals on
gel. Espesially if they are older crystals, sometimes you even see
higher molecular bands, these are probably due to intra molecular cross
links formed over time.
If you are worried about stability, try to increase the crystallization
speed, we have one example where we see a clear difference in both
crystal quality and even space group depending on when we fish the
crystals. The crystals appear within 5 min, the best quality data sets
come from crystals we fish after only 30-60 min.
You may also have a little protease contamination of course, to prevent
this add protease inhibitor, or DTT, or EDTA to you protein before you
set it up.
cheers Preben
On 1/16/13 12:14 PM, LISA wrote:
Hi All,
I have an 36KD protein which can be crystallize in two days. Most of
the crystals are very big. But all cystals have poor resolution,lower
than 3.8 A. I picked some crystals, washed them in the mother solution
and then run SDS-PAGE. It is surprised to find that different cystals
have different components. Some crystals have several samll bands
below the band of the protein. And in some crysals the bigger size
band (as the construct should be) almost disappared and have smear.
Does the protein was degradated in the crystals? Did someone met the
similar problem as I? Thanks
All the best
lisa
--
J. Preben Morth, Ph.D
Group Leader
Membrane Transport Group
Nordic EMBL Partnership
Centre for Molecular Medicine Norway (NCMM)
University of Oslo
P.O.Box 1137 Blindern
0318 Oslo, Norway
Email: [email protected]
Tel: +47 2284 0794
http://www.jpmorth.dk
