Thank you, everyone! Francesca ________________________________________ From: Enrico Stura [est...@cea.fr] Sent: Tuesday, February 17, 2015 3:00 AM To: CCP4BB@jiscmail.ac.uk; Mattiroli,Francesca Subject: Re: [ccp4bb] how to reduce protein solubility
Francesca, The most common failure is to have an excessive amount of salt (salting in/ salting out), glycerol or other solubilizing ingredient in your protein solution. I would suggest that you change the pH and reduce the salt in your protein solution, by microdialysis if you do not have much protein, and screen again. If share with ccp4bb the exact formulation of your protein solution you might get more suggestions. Enrico. On Tue, 17 Feb 2015 05:23:05 +0100, Mattiroli,Francesca <francesca.mattir...@colostate.edu> wrote: > Hi all, > > I am struggling with a protein complex that is too soluble. I have > reached about 20 mg/ml but I still observe very little precipitation > (clear drops in 90-95% of the tested conditions). The proteins are > expressed in insect cells and going to higher concentration is not > easily achievable. > I have tried different buffer conditions (salt concentration and pH) and > I am testing temperatures. I am at a loss with what to try next. > Do you think PTMs (phosphorylation, acetylation) might be causing this? > Any input on how to decrease solubility? > > Thank you very much in advance, > > Francesca > > -- 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 http://www-dsv.cea.fr/ibitecs/simopro/ltmb/cristallogenese LTMB, SIMOPRO, IBiTec-S, CE Saclay, 91191 Gif-sur-Yvette, FRANCE http://scholar.google.com/citations?hl=en&user=Kvm06WIoPAsC&pagesize=100&sortby=pubdate http://www.chem.gla.ac.uk/protein/mirror/stura/index2.html e-mail: est...@cea.fr Fax: 33 (0)1 69 08 90 71
