Fig. (4) Selectivity test of hits for G-quadruplex stabilization by polymerase stop assay. Compounds were tested in a Taq polymerase stop assay to evaluate specificity towards induction of G-quadruplex compared to inhibition of Taq by other mechanisms. Lane 1: Temp [TTAGGG]4, G-quadruplex forming template as control. Lane 2: Temp [TTAGGG]4 with 1 µM BRACO19. Lane 3: Temp [TTAGGG]4 with 50 µM BRACO19. Lane 4: Temp [TTAGAG]4, non G-quadruplex forming template as control. Lane 5: Temp [TTAGAG]4 with 1 µM BRACO19. Lane 6: Temp [TTAGAG]4 with 50 µM BRACO19. Lane 7: Labeled primer (P) at 15 nM with no template added. Lanes 8-9: NSC354961 at 5 and 50 µM. Lanes 10-11: NSC 305831 at 0.5 and 5 µM. Lanes 12-13: NSC 12155 at 5 and 50 µM. Lanes 14-15: NSC 35489 at 5 and 50 µM. Lanes 16-17: NSC 176327 at 0.5 and 5 µM.