hi thierry
we had a case where Spo0A in the phospho form was a dimer
in solution, and in the non-phospho form was a monomer. in the
crystal, we had monomers of the phospho form, and (domain-swapped)
dimers of the non-phospho form. turns out that the crystallisation
conditions affected the behaviour of the protein, converting a M->D
Kd from nanomolar to micromolar in the first instance, and the acid
pH of the crystallisation solution in the latter promoted domain-
swapping.
the biochemistry where we sorted all this out is:
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WK7-457CYHW-HN&_user=224739&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000014659&_version=1&_urlVersion=0&_userid=224739&md5=5d3b66d5d8d662753ec43bc94a173880
rick
Fischmann, Thierry wrote:
>
> Dear fellow crystallographers,
>
> This is a question which is not CCP4-related.
>
> Is anybody aware of a protein which is known to be a dimer in solution
> (say by SEC), and yet crystallizes as a monomer? Wouldn’t the high
> concentration in the crystallization drop further favor dimerization?
>
> In other words, if a protein crystallizes as a monomer, can I conclude
> that it does not form biologically relevant dimers in solution?
>
> Thank you in advance for your replies.
>
> Thierry
>
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