Hi Jack,
just a famous example:
The LIM region of a presumptive Caenorhabditis elegans transcription
factor is an iron-sulfur- and zinc-containing metallodomain.
Li PM, Reichert J, Freyd G, Horvitz HR, Walsh CT.
Proc Natl Acad Sci U S A. 1991 Oct 15;88(20):9210-3.
and
Cysteine-rich LIM domains of LIM-homeodomain and LIM-only proteins
contain zinc but not iron.
Archer VE, Breton J, Sanchez-Garcia I, Osada H, Forster A, Thomson AJ,
Rabbitts TH.
Proc Natl Acad Sci U S A. 1994 Jan 4;91(1):316-20.
another is
Free Radic Biol Med. 1999 Jul;27(1-2):193-202.
Expression, purification, and biochemical characterization of SAG, a
ring finger redox-sensitive protein.
Swaroop M, Bian J, Aviram M, Duan H, Bisgaier CL, Loo JA, Sun Y.
My own unpublished example is a DAG binding domain containing partially
a nice 3Fe-4S cluster instead of a Zn.
A brownish instead of a colourless protein solution is a good hint.
Best,
Guenter
> Dear Guenter,
>
> Would you mind sending me or posting on the ccp4bb the references to the cases you referred to in your message about eukaryotic Zn-proteins expressed in E.coli containing Fe instead of Zn?
>
> Thanks.
>
> Jack Tanner
>
>
>
>
> -----Original Message-----
> From: CCP4 bulletin board on behalf of Guenter Fritz
> Sent: Mon 8/6/2007 1:24 AM
> To: [log in to unmask]
> Subject: [Junk Mail] Re: [ccp4bb] Zinc or Iron binding protein, that is a question!
>
> Hi Xuan,
> I guess your protein is not an E.coli protein. There are several
> examples that eukaryotic Zn-proteins expressed in E.coli contain Fe
> instead of Zn. I am sceptic whether IMAC with different metal ions will
> give the solution of the problem. If you really want to get information
> on the metal ion binding properties you will have to do some matallo
> biochemistry: preparing apo protein, reconstitution with metal ions,
> UV-Vis spectroscopy, EPR would be great, ...
>
>
>> Dear Sir or Madam,
>>
>> The ICP-ES results indicated that 1 molar my protein purified from
>> E.coli Origami(DE3) contained about a half molar Zinc and nearly a
>> quarter molar Iron (whether II or III was not available). The protein
>> carried a MBP tag on the N-terminal and the situation was similar with
>> or without His tag at the C terminal. I want to determine whether my
>> protein really bind Zinc or Iron. Does anyone have any experience
>> about such problems?
>>
>> Specifically, now I want to compare the binding efficiency on various
>> IMAC, i.e. 50mM ZnSO4, FeSO4, Fe2(SO4)3, NiSO4(control), or
>> CuSO4(control). However, considering the instability of Fe(II) in
>> solution, the design still seemed problematic.
>>
>> Sincerely,
>>
>> Xuan Yang
>>
>> National Laboratory of Biomacromolecules and
>> Center for Infection and Immunity,
>> Institute of Biophysics,
>> Chinese Academy of Sciences,
>> Room 1617, 15 DaTun Road,Chaoyang District,
>> Beijing, China, 100101
>> Tel: 86-10-64884329
>> Academic email: [log in to unmask] <mailto:[log in to unmask]>
>> We will either find a way or make one.
>>
>>
>
>
>
>
--
***********************************
Priv.Doz.Dr. Guenter Fritz
Fachbereich Biologie
Sektion Naturwissenschaften
Universitaet Konstanz
http://www.biologie.uni-konstanz.de/fritz
Universitaetsstrasse 10
Postfach M665
D-78457 Konstanz
e-mail: [log in to unmask]
Phone Office: +49-(0)7531 88 3205
Phone Lab : +49-(0)7531 88 3733
Fax: +49-(0)7531 88 2966
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