Hi,
Anomalous map might give you some idea if it can be zinc.
~L~
______________________________________________________
Lari Lehtiö
Pharmaceutical Sciences, Department of Biosciences
Åbo Akademi University,
BioCity, FIN-20520 Turku
Finland
+358 2 215 4270
http://www.users.abo.fi/llehtio/
______________________________________________________
Quoting "Dr. STEPHEN SIN-YIN, CHUI" <[email protected]>:
Dear Daniel
Is the omit map for the model with and without the zinc ions
possible to confirm
its existence? I am curious. What is the resolution of dataset?
stephen
Quoting Daniel Bonsor <[email protected]>:
Hello again
I currently have some unexplained density in my structure. As you can
hopefully see from the images (see file), the density is dumbbell shaped.
Whatever it is, it is coordinated by Asp and Glu residues. To me it looks
like each lobe is a ring structure.
The crystallization condition was:
6.5% PEG 8K, 10mM ZnSO4, 100mM sodium cacodylate pH 6.5, 100mM Am2SO4, 1%
glycerol, with 20% glycerol as cryo.
Protein was originally in 50mM Tris, 50mM NaCl pH 7.5.
I originally placed a single Zn at the center of each lobe. Though after
refmac, the Zn was displaced to one side. Two zincs in each
dumbbell may have
worked, but I am dubious about two zinc atoms being 4A apart and there is
still some unexplained density. Are there any possible cyclization reactions
of Tris, cacodylate or glycerol may have undergone to explain the
density? Or
is it simply a highly ordered water network? Or is there some other
explanation?
Thanks in advance
Dan
--
Dr. Stephen Sin-Yin Chui
Research Assistant Professor,
Department of Chemistry,
The University of Hong Kong, Pokfulam Road,
Hong Kong SAR, China.
Tel: 22415814 (Office), 22415818 (X-ray Diffraction Laboratory)
