Eiso AB wrote:
> Albert,
>
> I think you mean ( or what is more ofter used is)
>
> (dH^2 + (dN/5)^2 )^(1/2)
>
> instead of (as it seems you write)
>
> (dH^2 + (dN^2)/5)^(1/2)
>
> Where the /5 represents a 0.2 scaling factor for the 15N CSP
>
> There are other values for this scaling factor. Mulder et al (J. Mol. Biol. (1999), 292: 111-123)
> find 1/6.4=0.156
>
> Theres a little discussion of this on
>
> http://qa.nmrwiki.org/question/181/relating-13c-and-1h-chemical-shifts-for-representation-of-2d-csps
>
> My own preference would be to take the root-mean-square of the scaled shifts
> ( dH^2 + (dN*cN)^2 / 2 )^(1/2) [cN=0.156] because this doesn't introduce an
sorry this should be
( ( dH^2 + (dN*cN )^2 )/2 )^(1/2)
> extra scalefactor compared to the cases where you get CSPs from only 1 nucleus
> or from more than 2 (e.g. CSPs from H,N,CO)
>
and for three nuclei....:\
( ( dH^2 + (dN*cN )^2 (dCO*cCO)^2 )/3 )^(1/2)
Eiso
> Eiso
>
>
> Albert Escobedo wrote:
>> Hi there,
>>
>> I am on my way to report my 15N HSQC titration results and a question has raised on how to do it. When using the "Follow
>> Shift Changes" panel, labels on "Traj Dist" and "Shift Dist" are descriptive but as long as no mathematical formalism is
>> specified I can not decide on which one to use to plot my data and set a significance threshold.
>>
>> I'd like to compare my results with published data where the following formalism is used to this end:
>>
>> deltaChemShiftav = ((deltaChemShift1H)^2 + ((deltaChemShift15N)^2)/5))^(1/2)
>>
>> where delta means increment, ChemShift is the chemical shift and av is average.
>>
>> My question is whether any of the two "Traj Dist" or "Shift Dist" is using this formalism and, if not, wich are the ones
>> being used?
>>
>> Thanks in advance,
>> Albert
>>
>
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