Re: [ccp4bb] Oligomer which lacks conformational cooperativity

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

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Subject: Re: Oligomer which lacks conformational cooperativity
From: Daniel Schlieper daniel {- dot -} schlieper {- at -} TUXOMANIA {- dot -} NET
Date: 2007-08-15

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Subject: "Dry" structures
From: "Sabini, Elisabetta" sabini {- at -} UIC {- dot -} EDU
Date: 2007-08-15

Subject: Re: Oligomer which lacks conformational cooperativity
From: Jacob Keller j-keller2 {- at -} MD {- dot -} NORTHWESTERN {- dot -} EDU
Date: 2007-08-15

I forgot to mention we also tried urea, at various concentrations.

JPK

==============Original message text===============
On Wed, 15 Aug 2007 11:39:14 am CDT Jacob Keller wrote:

Sorry about this not being exactly CCP4 related, but I think it is still of general interest to the
structural biology community:

I am dealing with a membrane protein which seems, on the surface, to present a contradiction:

We know from western blots and other data that this protein forms oligomers vehemently, which are
all but impervious to monomerization under the most ruthless conditions--we cannot completely
monomerize it. We have tried DTT, EDT, BME, all concentrations of SDS, PFO, temperature, and salt,
and in various combinations (further suggestions are welcome.) Suffice it to say, this thing is a
bona fide vicious oligomer.

Here is the paradox: the functional data, on the surface, seem to imply that the protein acts
independently, as if a monomer, without being influenced by its (tight) oligomeric partners, even
though we think the functional mechanism is a conformational change. Is such a thing observed in
the biochemical world? Are there any homo-oligomeric proteins out there, membrane-bound or
otherwise, which exhibit conformational changes, and yet the protomers do not influence each other?

If so, if the oligomerization has no functional significance, and the subunits do not exhibit
crosstalk, what on earth is the reason for their oligomerization?

All hypotheses and especially references would be greatly appreciated,

Jacob Keller

***********************************
Jacob Keller
Northwestern University
6541 N. Francisco #3
Chicago IL 60645
(847)467-4049
j-keller2@northwestern.edu
***********************************
===========End of original message text===========

***********************************
Jacob Keller
Northwestern University
6541 N. Francisco #3
Chicago IL 60645
(847)467-4049
j-keller2@northwestern.edu
***********************************

CCP4bb navigation

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

Previous message:
Subject: Re: Oligomer which lacks conformational cooperativity
From: Daniel Schlieper daniel {- dot -} schlieper {- at -} TUXOMANIA {- dot -} NET
Date: 2007-08-15

Next message:
Subject: "Dry" structures
From: "Sabini, Elisabetta" sabini {- at -} UIC {- dot -} EDU
Date: 2007-08-15