Hello,
it is not the first time that I see such electron densities near to His
residue.
However, in my structures (3N30, 3N32), I was sure that Zn, Pt or other
metals were present in the crystallization condition.
You have tried to refine with Zn rather than Mg that seems to be present
in the crystallization condition, but is there some reason or indication
that led you to follow this way? Maybe it's trivial to point out this,
but Zn is much more heavier than Mg and this can affect
occupancy/B-thermal factor of the refined atom. Strange values for
occupancy and B-thermal factor of your refined atoms (Zn and water) can
be a good indication about the correctness of your refining procedure.
The distance between N of His and water or metal are compatible with the
range expected for metals coordinated to Neps of Ndelta of His residue?
Have you try to refine with a more complex ligand, such as metal
coordinated to water molecules?
Danilo
Il 2014-03-08 06:28 SD Y ha scritto:
Hi,
During refinement, I see a strong density next to His and I have tried
metal ions and water but it seems to be different. Known components of
crystallization are Tris, NaCl, BME, MgOAc, PEG3350. Its only seen in
one chain of AU. Are there any suggestions?
Thanks in advance
SDY
