The concentration of recombinant proteins was generally unsuccessful as they tend to adhere to the membrane except in high salt buffer(>500mM NaCl) which would have interfered with the crystallography experiments. The highest concentration was able to obtained is 9mg/ml with one mutant protein which has a MW of 60 kDa. The rest of mutants proteins including the wild type have concentration varying from 4mg/ml to 7.5mg/ml (very low). However, concentration is an important condition for crystallization. 

Wild type MW : 90kDa 

C term mutant : 30 kDa

Other mutants have MW around 70 kDa. 

Please give me some advices about how to concentrate those proteins. 

Similar questions and discussions