Expression and purification of the rTgPuf1 Puf domain in E. coli . (A) Left panel shows a Coomassie Blue stained gel. Lane 1 and 2 shows the pellet and supernatant of lysates of induced pGEX-6P-1-TgPuf1-PUM-HD/BL21. Right panel is the immunoblot with anti-GST antibodies, which detected rTgPuf1 expression in uninduced (lane 3) and IPTG induced BL21 cells (lane 4). (B) Purification of rTgPuf1. Lane 1, lysate of induced BL21 cells; lane 2, lysate passed through a GST column; lane 3–7, elution with 50 mM Tris–HCl and 10 mM glutathione (pH 8.0).