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Hi,
        I am used to have the same problem with hydrophobic ligands, in special due to the rupture of crystals solely by the solvent even in tiny amount. So, I decided to mix a suspension of the ligand with the crystallization drop (once assured I can distinguish the protein from ligand). In addition, in order to avoid salt diffraction and ligand difusion out of the protein crystal, I usually "wash" (soak) crystals catch from these massy drops with a saturated solution of the ligand (say the supernatant of the ligand suspension in the crystallization solution after brief centrifugation).


regards, Mauricio





  On Jan 22, 2007, at 3:40 PM, Green, Todd wrote:


    Hello All,

    I am trying to soak some crystals with a small molecule that is quite hydrophobic. I am having trouble with solubilty of the small molecule. It will dissolve up to about 1 mM in 100 % DMSO, but precipitates at concentrations of less than 15 micromolar when the DMSO concentration is below 20 percent in my crystal growth solutions(which are peg 4k, low pH, low salt). Can anyone suggest solvents other than DMSO which might help dissolve the inhibitor and might be somewhat friendly to my crystals.

    Thanks in advance-
    Todd Green 



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