Hello everyone, I have a question about ion exchange chromatography. - I have a membrane protein (pI 9.5), 13 KDa - It's fused to MBP (maltose binding protein pI 5.1, 44 KDa) to prevent inclusion body formation during high level expresscion. - The final protein has a pI of 6.1, 57 KDa --> The protein is solublised in 1% TX, Tris 20 mM pH 8.0 20 mM NaCl. However, it doesn't bind to the column equilibrated in the same buffer condition.
Can anyone help me with this problem? Is it because of the pI difference between the membrane protein and the fusion partner? Many thanks
