High-throughput protein purification with ProA magnetic beads

The KingFisher® Flex system (Thermo Fisher) was used for high-throughput protein purification with magnetic ProA beads (GE Life Sciences). Briefly, 4 ml 293–6E cells in 24-well deep blocks were transfected for protein expression, followed by the addition of 100 μl magnetic ProA beads were added one day before harvest. Then, beads were collected and subjected to KingFisher purification with a 24 deep-well magnetic head. After washing 3 times with phosphate-buffered saline and twice with Milli-Q water, proteins were eluted with 500 μl of 100 mM sodium acetate at pH 3.6 for 10 min, and then immediately neutralized by adding 10 μl of 3 M Tris, pH 11.0.