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
<ganesh.natra...@ibs.fr> 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: est...@cea.fr Fax: 33 (0)1 69 08 90 71
