The CCP4 FFT program does the 90-degree rotation automatically if you
use "DANO=" as the column assignment. The rotation is because anomalous
difference arise from scattering that is 90 degrees out of phase with
"normal" electrons.
-James Holton
MAD Scientist
On 8/29/2014 11:43 AM, Alexander Aleshin wrote:
Could anyone remind me how to calculate anomalous difference Fourier maps
using model-calculated phases? I was doing it by
(1) calculating PHcalc from a pdb file using Sfall, then
(2) merging PHcalc with Dano of experimental SFs, then
(3) calculating a map with Dano and PHcalc using FFT program of CCP4.
Now, I've read Z. Dauter's et all paper
http://mcl1.ncifcrf.gov/dauter_pubs/175.pdf, and it said that their anomalous
maps were calculated using (delF, PHcalc-90degrees). Why did they use -90
degrees? How does it relay to a (delF, phcalc) map?
Thank you for an advice.
Alex Aleshin
