I would discourage using pre-made screens on a project outside the norm.
The main problems are:
Zinc: At mM concentrations will easily crystallize and give false positives
in many screens. It will also act as a precipitant for the peptide.
The best approach would be to separate the zinc adduct from the
non-complexed
to avoid heterogeneity.
During crystallization to avoid loosing the zinc it might be good to
add 50-200mM imidazole with 0.5-10mM zinc. You can either
add this to each precipitant solution (best) or to the peptide solution
(dangerous as it may all precipitate).
Then you can use precipitants except phosphate as it will give false
positives
avoid EDTA and other strong chelators (but weak chelators like imidazole
will be good).
If there are specific problems, many from CCP4BB will provide suggestions.
Enrico.
On Wed, 25 May 2011 14:04:23 +0200, Buz Barstow <[email protected]> wrote:
Dear all,
I am considering trying to crystallize a small peptide (around 15 amino
acids). The peptide is soluble in neutral water or buffer (pH 7.0) until
at least 10 mM (13 mg/mL), and adopts a turn conformation when bound to
Zn.
What are your thoughts on attempting this?
If you think that it is worthwhile, what crystallization conditions
would you try? I am thinking of a sparse matrix screen using the Hampton
Crystal Screen 1 and 2 kits, using hanging drop crystallization in
Hampton Vdx trays.
Thanks! and all the best,
---Buz
--
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: [email protected] Fax: 33 (0)1 69 08 90 71
