like others I'm not clear why you care where your protein runs on SDS-PAGE. I think the band you're seeing is in fact the tetramer, suggesting your protein (like KcsA) is very stable. Helical membrane proteins often migrate faster than expected (by their Mw) on SDS-PAGE.
Also, never boil helical membrane protein samples, they will aggregate. bert ________________________________ From: CCP4 bulletin board <[email protected]> on behalf of amit gaur <[email protected]> Sent: 21 February 2017 22:22 To: [email protected] Subject: [ccp4bb] Dimer in SDS-PAGE Hi all, I am trying to purify a potassium ion channel from insect cell using baculovirus expression system. I am not seeing monomer of this protein in SDS instead a dimer appears.So,I increased DTT in SDS buffer but no change and dimer was intact. In size exclusion this protein appeared as a tetramer which is common oligomerizaton of potassium channel family with GYG motif. Can any body suggest what should I do in this case? Thanks and regards, -- Dr. Amit Gaur Post Doctoral Researcher PI: Dr. Ji-Fang Zhang Thomas Jefferson University 1020, Locust Street, Suite 418 Philadelphia, PA 19107
