Re: [ccp4bb] removal of sulfate ion from the active site

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

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Subject: AW: removal of sulfate ion from the active site
From: Herman {- dot -} Schreuder {- at -} SANOFI-AVENTIS {- dot -} COM Herman {- dot -} Schreuder {- at -} SANOFI-AVENTIS {- dot -} COM
Date: 2007-05-25

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Subject: Antwort: removal of sulfate ion from the active site
From: Djordje {- dot -} Musil {- at -} MERCK {- dot -} DE Djordje {- dot -} Musil {- at -} MERCK {- dot -} DE
Date: 2007-05-25

Subject: Re: removal of sulfate ion from the active site
From: Dirk Kostrewa dirk {- dot -} kostrewa {- at -} PSI {- dot -} CH
Date: 2007-05-25

Hi Yue Li,

are you sure that it's the sulfate that competes with the inhibitor
binding, say, from enzymatic test? It could be, but it is known that
sulfates and phosphates usually prefer different binding sites ...

Best regards,

Dirk.

Yue Li wrote:
> Hi all,
>
> I have crystals of the apo enzyme growing from 1.7M ammonium sulfate
> condition. After soaking with 10mM ligand (substrate analog) which has a
> phosphate group, the ligand did not enter the active site of the enzyme
> because of the competition of sulfate ion and phosphate group. So I am
> wondering if anyone knows how to get rid of ammonium sulfate from
> crystal before soaking it with the ligand solution? Thanks a lot.
>
> Simon

--

****************************************
Dirk Kostrewa
Paul Scherrer Institut
Biomolecular Research, OFLC/110
CH-5232 Villigen PSI, Switzerland
Phone: +41-56-310-4722
Fax: +41-56-310-5288
E-mail: dirk.kostrewa@psi.ch
http://sb.web.psi.ch
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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999