Thanks to all who replied to my message.
The most logical explanation to the observed phenomenon is likely the
following. During crystallization, Sr ions from the crystallization solution
kick out a fraction of the Mg(OH)6 ions from the binding site in question. The
cavity of the binding site
Dear All,
We are looking for an explanation for a very strange observation.
Problem:
We have two fully independent data sets (two different crystals), in which the
Bijvoet Difference Fourier map peak of one particular metal site is shifted by
0.47 A from its position in the 2Fo-Fc map.
A technecality - the Dano only contains information about anomalous
scatterers and should therefore show these more precisely.
The 2Fo-Fc map will tend to show anything which is included in the phasing
at the position given.
For safety you can set all the atom occupancies in the vicinity of the
Hi Petr,
A few thoughts:
1) The Bijvoet difference Fourier is an approximation to the true imaginary
part of the electron density, and because of this shifts in the positions
of peaks in this map relative to the 2Fo-Fc map might be expected. This is
described in Hendrickson et al. Acta Cryst A43
Dear Petr Leiman :
It could be the result of series termination in anomolous map.(not sure)
The error in the position results in a shifted position in the 2Fo-Fc map.
As a check it is worthwhile to see an average of the two positions (three
coordinates) results in a feature consistent with
