Re: [ccp4bb]: Cys modification

[Manfred Weiss <msweiss@imb-jena.de>]

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Dear Jeff,

If your cysteine gets 'ears' (i.e. density on both sides of
the sulfur at a distance of about 1 A) that could be a sign
of anisotropic mobility of the sulfur. This could potentially
show up at 1.7 A already.

-Manfred.

> 
> I've also been wondering about extra density that I see near the two
> cysteines in the model I'm working on.  The data are up to 1.7A and were
> collected at 100K.  Replacing the SH with SO3 does not fit well, in
> either case.  The extra density is to one side of the sulfur and I
> currently have it modeled as a magnesium ion.  Water doesn't fit well
> either, as it can't get close enough.
> 
> Is this common?  I checked a sub set of the pdb and did not find any
> metal ions near cysteines.
> 
> Jeff Taylor
> -- 
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Dr. Jeffrey S. Taylor       Duke University Medical Center
> Department of Biochemistry  Box 3711, Nanaline Duke Bld  
> Phone (919) 681-5266        Durham, NC 27710
> 


-- 

 Manfred S. Weiss, Dr.
 Institute of Molecular Biotechnology
 Department of Structural Biology and Crystallography
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