On Tue, 2012-10-30 at 16:12 +0000, Peter Hsu wrote:
> I'm wondering, since I lack activity at this pH point, would it lead
> to no binding of a substrate analog?
Not necessarily. You should check pH dependence of the Km - it might be
that lower activity is primarily due to reduction in kcat. Binding
studies are always a good idea before trying to soak/cocrystallize.
With that said, it's entirely possible that you don't see ligand in the
electron density because the enzyme is stuck in a wrong conformation or
binding site is blocked.
I wonder if you can get resolve pH issue by cross-linking the crystals
at which point you can use whichever soaking buffer pH you want
(assuming no loss of diffraction)
Cheers,
Ed.
--
"I'd jump in myself, if I weren't so good at whistling."
Julian, King of Lemurs
