check an anomalous map!
The obvious thing to do to rule out gold binding
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Dr. Matthias Zebisch
Division of Structural Biology,
Wellcome Trust Centre for Human Genetics,
University of Oxford,
Roosevelt Drive,
Oxford OX3 7BN, UK

Phone (+44) 1865 287549; 
Fax (+44) 1865 287547
Email [log in to unmask]
Website http://www.strubi.ox.ac.uk
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On 12/10/2013 12:44 PM, PriyankMaindola wrote:
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dear members

i am trying to solve this crystal structure but 
​I am puzzled with an​
 undefined  blob
​ that​
 
​appeared at a glutamine residue after refinement. I have attached pics of that below. 
Is it a covalent modification of acid-amide side chain..
​... as there is no charged environment around and density seems continuous.

​please suggest
....

following reagents were encountered by protein
​ during purification, crystallization and soaking​
:
phenyl methyl sulfonyl fluoride
benzamidine
tris
dtt
​  (could it be cyclized dtt?)​

k[au(cn)2]
acidic pH
isopropanol
citrate
sulfate
phosfate
K+, Na+, Cl-

​ map contour:
2fo-fc: 1rmsd
fo-fc (green): 3 rmsd​


-- 
Priyank