Dear Klaus
If your compound can be dried, you can add it to the drop as a powder
from the tip of a acupuncture needle. At least this works for many of
the insoluble heavy metal derivatives. We have also successfully
resuspended the powder in the optimal buffer of choice and added it as
insoluble power in solution.
cheers
Preben
On 5/23/13 3:36 PM, Klaus Fütterer wrote:
Dear CCP4BB followers,
We are currently trying to obtain ligand-bound complexes for one of
our proteins by soaking and/or co-crystallisation. We have had prior
success for this protein, but using a different class of ligands. The
new ligand (in DMSO) remains in solution (more or less) when mixed
with the reservoir/cryoprotectant, and the diffraction pattern
survives the soaking nicely. Annoyingly though, all we see are
density peaks that match the size of DMSO and become more pronounced
when increasing [DMSO] (to help solubilisation of the ligand). Soaking
times varied between minutes to 16 hours. Kd was measured ( ~ 10 uM)
in the solution state.
We have tried pyridine (which keeps the ligand in solution, but kills
diffraction in an instant), and DMF (which doesn't keep the ligand in
solution when mixing with cryoprotectant).
I am wondering whether the community has suggestions for alternative
organic solvents that have been used to solubilise hydrophobic
ligands, and are reasonably gentle to the protein crystal.
Thank you.
Klaus
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Klaus Fütterer, Ph.D.
Reader in Structural Biology
Undergraduate Admissions
School of Biosciences P: +44-(0)-121-414 5895
University of Birmingham F: +44-(0)-121-414 5925
Edgbaston E: k.futte...@bham.ac.uk
<mailto:k.futte...@bham.ac.uk>
Birmingham, B15 2TT, UK W: http://tinyurl.com/futterer-lab
=======================================================================
--
J. Preben Morth, Ph.D
Group Leader
Membrane Transport Group
Nordic EMBL Partnership
Centre for Molecular Medicine Norway (NCMM)
University of Oslo
P.O.Box 1137 Blindern
0318 Oslo, Norway
Email: j.p.mo...@ncmm.uio.no
Tel: +47 2284 0794
http://www.jpmorth.dk
