Dear Roger,
I disagree with Ganesh. Knowing the stoichiometry is not necessary.
Stoichiometry
may need adjusting to reflect the relative solubility of the interacting
partners
under the various crystallization conditions.
See also:
Stura, E.A., Graille, M., Taussig, M.J., Sutton, B.J. Gore, M.G.,
Silverman, G.J. & Charbonnier, J.-B. (2001) Crystallization of
macromolecular complexes: Stoichiometric variation screening. J. Cryst.
Growth 232: 580-590.
Affinity is very important when the affinity is better than nanomolar, you
do not need stoichiometric
compensation.
Enrico.
On Fri, 07 Dec 2012 16:44:48 +0100, Ganesh Natrajan
<[log in to unmask]> wrote:
> Dear Roger,
>
> In my humble opinion, the qualitative knowledge that the complex
> actually forms (established through pull down assays, gel filtration
> etc) is probably far more important than the Kd values in solution. In
> any case, the crystallization is done at very high concentrations, far
> above the Kd values of the interacting partners. So having a thumb rule
> is not necessary. The knowledge of the stoichiometry of the binding
> partners may actually be more important to get a more homogenious
> complex.
>
> In a recent complex I've worked on, we determined the Kd only after
> solving the structure.
>
> .
>
> cheers
>
> Ganesh
>
>
>
> Le 07/12/12 16:11, Roger Pickman a écrit :
>> Dear all - is there a rule of thumb for favourable values of Kd, kon
>> and koff of protein-protein or protein-dna complexes for protein
>> crystallisation? Are these measurements useful in crystallisation, or
>> should one just put it down a gel filtration column, hope for a
>> complex and not worry? If anyone can point toward a reference, i'd
>> appreciate it.
>>
>> Roger
>
--
Enrico A. Stura D.Phil. (Oxon) , Tel: 33 (0)1 69 08 4302 Office
Room 19, Bat.152, Tel: 33 (0)1 69 08 9449 Lab
LTMB, SIMOPRO, IBiTec-S, CE Saclay, 91191 Gif-sur-Yvette, FRANCE
http://www-dsv.cea.fr/en/institutes/institute-of-biology-and-technology-saclay-ibitec-s/unites-de-recherche/department-of-molecular-engineering-of-proteins-simopro/molecular-toxinology-and-biotechnology-laboratory-ltmb/crystallogenesis-e.-stura
http://www.chem.gla.ac.uk/protein/mirror/stura/index2.html
e-mail: [log in to unmask] Fax: 33 (0)1 69 08 90 71
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