title: SELEX library
design: With the SELEX libraries ready, an EMSA gel was prepared to separate the bound DNA fragments from the unbound. To prepare a gel for EMSA, 3.5ml of 5 TBE, 3.1ml of 30% acrylamide/bis-acrylamide solution (37.5:1), 2.3ml of 40% acrylamide solution, and 1.1ml of 80% glycerol were added to 24.25ml of water. The mixture was mixed well, avoiding the generation of bubbles. Then, 262.5μL of 10% ammonium persulfate and 17.5μL of TEMED were added to catalyze polymerization. The solution was briefly mixed, poured into a mold to form a gel, and allowed to solidify for 1 hour. After solidification, the wells of the gel were flushed with 0.5 TBE to remove unpolymerized acrylamide, and the gel was pre-run for 10 minutes at 150 V in 0.5 TBE buffer. The gel was run in a cold room at 4C.