We have had success concentrating protein by dialyzing the sample against buffer plus 10-15% high molecular weight PEG (8-10k). It takes some trial and error to get the right concentration; sometimes it helps to do a stepwise procedure, gradually increasing the amount of PEG. Hope this helps!
Best Regards, Allyn > Dear all > > For crystallisation assays and other experiments, I want to concentrate > 2 protein-DNA complexes purified by gel filtration. > > - The affinity of the protein for the DNA is 10 nM. > - I could concentrate the protein until 1.5 mg/ml (= 38 µM) > - I have already tried lyophylisation (before and after complex > creation) or amicon method without results (I can't manage to increase > the concentration). > - The complex could be a dimer or a tetramer on the DNA > > Do you have any good idea about this????? > > Thank you for your help and sorry for my first incomprehensible mail > > CHAIX Denis > > Centre de Biochimie Structurale > INSERM U554/CNRS 5048 > 29 rue de Navacelles > F-34090 Montpellier, France > Tel: 33 4 67 41 77 21 > Fax: 33 4 67 41 79 13 > e-mail:[EMAIL PROTECTED] > http://www.cbs.cnrs.fr > -- Allyn J. Schoeffler Berger Lab Dept. of Molecular and Cell Biology UC Berkeley phone: (510) 643-9491
