Hello,
If you let:
d1 = delta1 * scaleFactor1
d2 = delta2 * scaleFactor2
(so delta1, scaleFactor1, delta2 and scaleFactor2 as specified in the
dialog) then:
shiftDist = sqrt(d1*d1 + d2*d2)
shiftSum = abs(d1) + abs(d2)
Wayne
On Mon, 24 Jan 2011, shixiong lua wrote:
> Hi wayne,
>
> could you provide the formula used for calculating the shift distance under
> data analysis: Shift differences ?
>
>
>
> On Mon, Jan 24, 2011 at 9:15 PM, Wayne Boucher <[log in to unmask]>
> wrote:
> Hello,
>
> That first equation is to be used when you have a monomer-dimer
> in fast exchange. The second equation is to be used when you
> have protein-ligand in fast exchange. Neither equation will
> make sense in other circumstances and so could easily give
> funny answers. (But I also seem to remember that the parameter
> fits could be sensitive to the data for at least the second
> equation, in cases when the data was not sufficiently sampled
> for the whole curve.)
>
> I've attached a PDF file describing these two equations, in
> case anyone is interested. (The first equation below is
> described in the second section and the second equation below
> in the first section, to be confusing.)
>
> Wayne
>
>
> On Mon, 24 Jan 2011, shixiong lua wrote:
>
> hi team,
>
> i was using the "follow shift changes" function of ccpnmr
> and discovered a bug.
>
> when i chose the fiiting function:
> A((B+4x-sqrt((B+4x)^2-(4x)^2))/4x-c), the Kd fitted
> was all negative values.
>
> i thus changes to another function
> A(B+4x-sqrt((B+x)^2-4x)) which does not fit very
> well but gives sensible Kd values.
>
> When i was looking at the <fit graph> window for each
> spin system, i manually changed
> the fitting function from the drop list in the <fit
> graph> window itself. But instead
> of reporting an insensible negative Kd value, it showed a
> reasonable value.
>
> please look into this matter
>
> --
> Warm Regards,
>
> Lua
>
>
>
>
> --
> Warm Regards,
>
> Lua Shixiong (Mr) :: Graduate student :: Department of Biological Sciences
> :: Structural biology Lab :: National University of Singapore :: Block S3,
> Level 4, Lab 3, Science Drive 4, Singapore 117543 :: 6 516 1209 (Office) ::
> [log in to unmask] (Email)
> (\ /)
> (O.o)
> (> <)
>
>
>
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