On 09/24/2012 07:09 AM, Harm Otten wrote:
Why is it so hard to break the symmetry for two (seemingly) different monomers?
Because it's present in your data?
In P1, do you still have the electron density that suggests the
overlap (it's not entirely clear to me what you mean by that - a
Beamtime is currently available for the fall 2012 run, now through November 19,
at the Cornell High Energy Synchrotron Source (CHESS, in Ithaca NY). The
facility offers:
Monochromatic stations A1 and F1, at 12.7 and 13.5 KeV, with ADSC CCD detectors,
ALS-style crystal automounters,
Hi All,
I've recently swapped over to expression in the ArcticExpress(DE3) cells
for a particularly rock-like protein. I've got soluble expression but I'm
having the issue of Cpn60 (the overexpressed chaperonin) piggybacking along
with the tagged protein. Google-fu and the CCP4bb archives
Incubation with MgCl2/ATP/KCl facilitates the release of the Cpn60.
See: R. E. Joseph; A. H. Andreotti, Protein Expr. Purif. 2008, 60, 194–197.
Best,
Cynthia
__
Cynthia Kinsland, Ph. D.
Director, Protein Production Facility
Cornell University
B78 ST Olin
Dear Harm,
As Edwin pointed out, there might not be any non-crystallographic symmetry to
break, because it is crystallographic. While it is clear that no two N-terminii
can be in the same electron density at the same moment, there is no reason why
this symmetry-breaking should happen in a
Hi Katherine,
Maybe you can try some useful ideas for your case listed in this study:
Protein Expr Purif. 2007 April; 52(2): 280–285.
Effect of Osmotic Stress and Heat Shock in Recombinant Protein
Overexpression and Crystallization.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1865119/
Best wishes
Dear Crystallographers:
#off topic
I am trying to calibrate some microscopic imaging intracellular pH
measurements, but the usual nigericin (small pore-forming K+/H+ exchanger)
technique does not seem to be working well. Maybe it actually never works
well? Anyway, I was think of trying to use
Hi All,
My protein can be solubilized in 8M Urea or detergents. Could anyone suggest me
whether ammonium sulfate precipitation of my desired protein works good for
denaturing conditions?
Thanks a lot for your help!
Regards,
Koyeli
Off the top, I don't know the answer to this, but will note that
ammonium sulfate and urea have opposite effects on protein solubility
and water structure. Urea is a chaotrope that reduces the strength of
the hydrophobic effect--hence promoting protein unfolding. Ammonium
sulfate is a
