Hello all,
I am having the same issues as Conny. As an additional note, I ran into this problem after I performed an update on Friday. I hadn't downloaded updates since February and prior to updating, I had no problems grouping peaks and fitting.
As for the fitting equation, it would be very useful to have a prompt for protein concentration and use the following equation to fit to a ligand concentration titration series.
ChemShiftChange= (Kd + [ligand] + [protein] - Sqrt[(Kd + [ligand] + [protein])^2 - 4*[ligand]*[protein]])/(2*[protein]) *maxChemShiftChange
(For an example, see PNAS 2008 vol. 105 (2) pp. 506-11)
Thanks -- Lisa
On Sun, Jun 1, 2008 at 10:21 AM, Conny Johanssin
<[log in to unmask]> wrote:
> I've been making some titrations lately and have run into some trouble
> analysing the data.
>
> 1) When I make histograms of resonance1 vs shift dist The resonances are not
> displayed on the x axis, but they are for other people in the lab. Still we
> are all using the same installation of Analysis. See attachment for screenshot.
>
> 2) When I try to fit my titration to the saturation curve function in
> analysis (the longest function, 2nd from bottom) and then press group peaks
> I get a error (see screen dump). The annoying thing is that I got it to work
> with another titration 2 weeks ago, but not this time. I've tried both
> ligand ratio and ligand conc.
>
> 3) When I managed to fit the function 2 weeks ago I got a really nice
> fitting curve and equation (with the variable values). Theoretically, I
> should be able to derive the Kd from this function. It would be really nice
> to be able to do that right away in Analysis rather than using some other
> program. Anyhow, I don't recognize the equation and I find it strange that
> it doesn't need the protein concentration, just the ligand. Do you have some
> kind of reference on this equation where I can read about it, or where does
> it come from? Do you know how I can get the Kd from the equation?
>
> Thanks
> Conny
>
--
Lisa R. Warner
Graduate Student
Dept. of Biochemistry
University of Colorado, Boulder
215 UCB
Boulder, CO 80309-0215
303.492.8085
--
Lisa R. Warner
Research Assistant
Dept. of Biochemistry
University of Colorado, Boulder
215 UCB
Boulder, CO 80309-0215
303.492.8085
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