In addition to the other very good suggestions, you could consider using a purification tag at both the N- and C-termini of your protein to only pull out full length protein. I've had success with Flag+His and MBP+His.
Ho Ho Leung Ng University of Hawaii at Manoa Assistant Professor, Department of Chemistry [email protected] On Tue, Aug 21, 2012 at 1:00 PM, CCP4BB automatic digest system <[email protected]> wrote: > > Date: Tue, 21 Aug 2012 21:15:15 +0100 > From: Theresa Hsu <[email protected]> > Subject: Purify non-stable protein > > Dear all > > I made deletion mutation of a stretch of 20 amino acids on my protein. I can > purify and crystallize wild type protein but not the mutated. Mass spec on > gel separated protein shows degradation of mutant losing about another 150 > amino acids. Is there any way of purifying this non-stable protein? I know > nature has designed proteins to be stable. > > All steps are done at 4 C and protease inhibitor added during cell lysis for > both proteins. > > Thank you.
