hi guys, I have a DNA binding protein and expressed the DNA binding domain (150 aa) with his-sumo tag or gst tag at the n-terminal. I tried to purified it with Ni column or Gst column separately. But purity is lower than 50% after Ni or GST column. This protein only stable with 1M Nacl or higher. I worked on it almost half year. But I still can not get the pure protein. please give me some suggestions. Thank you.
Lisa
