Try adjusting the pH close to the pI to reduce solubility.
> From: Yvonne Leduc <[EMAIL PROTECTED]> > Reply-To: <[EMAIL PROTECTED]> > Date: Tue, 7 Aug 2007 10:17:18 -0600 > To: <[email protected]> > Subject: [ccp4bb] highly soluble proteins > > Our lab is trying to crystallize a highly soluble (100+ mg/ml) protein > with a molecular weight of 35 kd. > > The protein was screened against 1536 conditions at 20 mg/mL. Most drops > were either clear or produced "bubbles" (often oily looking). The few > that had precipitate contained high concentrations of K3PO4, cobalt, or > zinc. We have tried repeating some of the bubble conditions at 100+ > mg/mL and are still getting clear drops or bubbles. > > Is there something about highly soluble proteins and/or secreted > proteins and/or proteins with unusual portions of their sequence that > needs to be considered in order to successfully crystallize it? > > I am considering trying "salting out" using dialysis, and also adding > ligands/inhibitors. The protein is in 50 mM NaCl plus 50 mM buffer. > > I welcome thoughts and suggestions on crystallization ideas, > publications, etc. > > Thank you > > Yvonne
