[ccp4bb]: Re: [o-info] metal ion

["Eleanor J. Dodson" <ccp4@ysbl.york.ac.uk>]

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baber akbar wrote:
> 
> Dear Friends,
> 
>         I solved a mutanst structure.  I found
> one additional metal ion inaddition to the existing
> one with six coordinations (three protein atoms and
> three water molecules).  I suspect that it may
> be calcium or chloride ion.  How do I confirm it.
> Biochemical studies revealed that there is no
> second metal ion in the sample.  Please let me
> know how to go about it.
> 
> = Himayoon
> 


 You can often get a clue by looking at a Dano map - Ca and Cl have very
different anomalous contributions. Compare your peak heights to the S
ones.

 All this presumes you have kept your anomalous signal - this should be
mandatory for ALL data processing scripts! Even very partial anom
dispersion information can answer this sort of Q.

 Eleanor

 Eleanor