Re: [ccp4bb] Mg++ binding to N7 of G

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

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Subject: Production of recombinant membrane protein complex in E. coli
From: ywc ywc {- at -} GATE {- dot -} SINICA {- dot -} EDU {- dot -} TW
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Subject: Re: Mg++ binding to N7 of G
From: Pirkko Heikinheimo Pirkko {- dot -} Heikinheimo {- at -} HELSINKI {- dot -} FI
Date: 2008-04-03

Subject: Re: Mg++ binding to N7 of G
From: Martin Hallberg Martin {- dot -} Hallberg {- at -} KI {- dot -} SE
Date: 2008-04-03

Hi Bill,

On Apr 2, 2008, at 10:58 PM, William G. Scott wrote:
>
> I've got what appears to be an inner-sphere interaction between Mg++
> and the N7 of a G. The mode of binding is the same as what is
> observed at this site for Mn++, confirmed with anomalous data. Our
> resolution is 1.6 Å, so I am reasonably confident this is right.
> However, my chemist's viewpoint is that Mg++ is too hard and N is
> too soft for this to happen.
>
I would also be hesitant.
>
> Since Mg++ has the same number of electrons as water and no useful
> absorbance, it seems assigning them based on hydration geometry and
> bond distances is the only hope.
>

One can often see magnesium ions in anomalous-difference fouriers with
good home-source data. Since you appear to have very good diffraction
and your magnesium is most definitely relatively well ordered (if it
is a magnesium..) I think it is worth a try to carefully collect a
data set using a wavelength around 1.5-1.6 Å (or simply your home
source depending on how good it is).

Cheers,

Martin

.
B. Martin Hallberg, PhD
Assistant professor
Department of Cell and Molecular Biology
Medical Nobel Institute
Karolinska Institutet
Nobels väg 3
SE-171 77 Stockholm
Sweden

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

Previous message:
Subject: Production of recombinant membrane protein complex in E. coli
From: ywc ywc {- at -} GATE {- dot -} SINICA {- dot -} EDU {- dot -} TW
Date: 2008-04-03

Next message:
Subject: Re: Mg++ binding to N7 of G
From: Pirkko Heikinheimo Pirkko {- dot -} Heikinheimo {- at -} HELSINKI {- dot -} FI
Date: 2008-04-03