[phenixbb] Double difference anomalous maps
pafonine at lbl.gov
Tue Nov 9 17:13:04 PST 2021
> I tried the "Isomorphous difference map” action and specified a file
> for input 1 containing F1+, F1– at one wavelength, and the file input
> 2 containing F2+,F2– at another wavelength. I selected the appropriate
> Labels for the columns containing the anomalous data. I then
> specified in "Advanced Options” to *use anomalous differences instead
> of amplitudes*. Will this procedure use the following coefficients
> for the difference Fourier?
> ( F1(+) – F1(–) ) – ( F2(+) – F2(–) ), alpha(calc)
> Can someone confirm if this is indeed what is calculated?
no, not quite.. Given two data sets, Fobs1 and Fobs2, and a phase source
(eg., atomic model), it computes
Fourier map. Both data sets are assumed to be collected from isomorphous
crystals (same space groups, unit cells can deviate up to a small
Phenix treats Fobs(+) and Fobs(-) as individual data points, so in the
map above they will participate as, for example
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the phenixbb