I am trying to find the binding partner of Msp1b1 (outer surface protein of Anaplasma marginale) on DAE 100 (Tick cells). First, I tried Ni-NTA beads and my binding buffer contains 20mM Tris HCl,250mm NaCl, and 50mM imidazole, and wash buffer 1 ( used before Lysate) was 20mM Tris HCl,250mm NaCl and 20mM imidazole and wash buffer 2( used after Lysate was 20mM Tris HCl,250mm NaCl. I am boiling my beads instead of eluting them. The result was getting a lot of background.

Now I switched to Dyna beads where my 2x binding/washing buffer was Sodium phosphate pH8 100mM, NaCl 600mM, Tween 20 0.02% and 2X pulldown buffer was Sodium phosphate pH 7.4 6.5mM, NaCl 140mM, Tween-20 0.02%. and His elution was Imidazole 300mM, Sodium phosphate pH8 10mM and 300mm NaCl and Tween-20 0.01%.The result was with less background but alot less bands.