If your goal is a crystal structure, this reference may be worth consulting. The paper describes the use of centrifugal concentrators to make a complex of two proteins that have Kd of 19 micromolar for crystallization. They mixed the two proteins and then concentrated using a membrane that allows passage of the smaller protein while retaining the complex. The protein-protein complex crystallized.
Ignatev A, Piatkov K, Pylypenko O, Rak A. A size filtration approach to purify low affinity complexes for crystallization. J Struct Biol. 2007 Jul;159(1):154-7. PubMed PMID: 17408969. John J. Tanner Professor of Biochemistry and Chemistry Chair, Biochemistry Department Graduate Admissions Committee Department of Biochemistry University of Missouri-Columbia 117 Schweitzer Hall 503 S College Avenue Columbia, MO 65211 Phone: 573-884-1280 Fax: 573-882-5635 Email: tanne...@missouri.edu<mailto:tanne...@missouri.edu> http://faculty.missouri.edu/~tannerjj/tannergroup/tanner.html Lab: Schlundt Annex rooms 3,6,9, 203B, 203C Office: Schlundt Annex 203A On Jan 31, 2017, at 10:05 AM, sanjeev kumar <sanjeev....@gmail.com<mailto:sanjeev....@gmail.com>> wrote: Dear all, I am trying to stabilize a protein-protein complex. Our SPR study indicates it is having micro molar dissociation constant. I tried to purify both the molecule in complex form with size exclusion chromatography (mixed both the protein in equal molar ratio and incubated at 4 degree for 1 hour), I didnt observed formation of complex as both the molecule eluted at their respected elution volume. Please suggest me to get a better way to achieve the complex and if anyone gives idea about what is the good cross-linker I can use. Suggestions are highly appreciated. Thanks best sanjeev kumar, PhD Purdue University West Lafayette Indiana
