There was a paper a couple years ago that suggested very low
concentration of glycerol (I think 0.5%). I recently did some
systematic comparisons of different glycerol concentrations and found
that higher concentrations do seem to worsen the so-called
concentration effects. This makes intuitive sense. Adding glycerol
may effectively decrease the solubility of a protein and so the
solution behaves more like a concentrated solution with correlations
between particles in the structure factor. Only speculation at this
point of course. I also worry about glycerol effecting the oligomeric
state of a protein. Nonetheless, it seems to be a good thing in low
concentrations.
Working at 4C may help.
Richard Gillilan
MacCHESS
On Jul 9, 2009, at 8:57 PM, Susan Tsutakawa wrote:
Hi Bill,
5-10% glycerol usually helps in the majority of cases. However,
some proteins require a scan of different conditions and different
protein concentrations. Like everything else, it's protein
dependent. Changing the wavelength can also make a difference. I
also know some SAXS beamlines like at the APS have capillary flow
cells so they just do hit and runs.
Susan
