Re: [ccp4bb] Sulfate ion on 2-fold axis

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

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Subject: unbiased electron density map
From: michael nelson gnomenm {- at -} YAHOO {- dot -} COM
Date: 2008-01-09

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Subject: Re: unbiased electron density map
From: William Scott wgscott {- at -} CHEMISTRY {- dot -} UCSC {- dot -} EDU
Date: 2008-01-09

Subject: Re: Sulfate ion on 2-fold axis
From: Dale Tronrud det102 {- at -} UOXRAY {- dot -} UOREGON {- dot -} EDU
Date: 2008-01-09

Dear Jie,

It also depends on whether you believe the SO4 sits
with its internal two-fold along the crystal's two-fold
axis. If it does you should probably have a 0.5 occ
sulfur and two 1.0 occ oxygen atoms. If the symmetry
is not obeyed you will have to have four 0.5 occ oxygen
atoms.

Be careful, some refinement programs will not be able
to handle the bond length and angle restraints if you
only supply two oxygen atoms. They will not allow
bonds between atoms and symmetry images of atoms. If
you are using such a program you will have to supply
four oxygen atoms even if this is not what you would
otherwise do.

Dale Tronrud

Charlie Bond wrote:
> Hi Jie,
> Depending on your resolution, you may be forced use to use S(0.5) and
> 4x(0.5) in order to restrain the SO4 to stay tetrahedral in refinement.
> Cheers,
> Charlie
>
>
> Jie Liu wrote:
>> Dear all
>>
>> I have a sulfate ion sitting on a 2-fold axis. Should I put in pdb file
>> one S atom with occu=0.5 and two O atoms with occu=1, or should
>> I put one S and four O atoms all with occu=0.5?
>>
>> Thanks for your inputs.
>>
>> Jie
>>
>> .
>>
>

CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: unbiased electron density map
From: michael nelson gnomenm {- at -} YAHOO {- dot -} COM
Date: 2008-01-09

Next message:
Subject: Re: unbiased electron density map
From: William Scott wgscott {- at -} CHEMISTRY {- dot -} UCSC {- dot -} EDU
Date: 2008-01-09