Evaluation of impact of different ions on G-quadruplex formation when <i>BCL2</i> mbr is present on oligomeric DNA substrates.

<p><b>A.</b> Schematic representation of the oligomers used in the study. BTM1 (C) is the complementary sequence of G-quadruplex forming sequence and BTM2 (G) represents the G-quadruplex forming sequence of <i>BCL2</i> mbr. BTM4 (G₆) represents the mutant form of BTM2 (G) where 6 Gs are mutated (indicated in blue color). <b>B-E.</b> Different oligomeric DNA, BTM1, BTM2 and BTM4 were incubated either in TE buffer (B), TE + KCl (C), TE + NaCl (D) or TE + LiCl (E) at 37°C for 1 h and resolved on a 12% native PAGE at room temperature. In all cases both the gel running buffer (TBE) and gel contained respective ions (100 mM). Formation of intermolecular species are marked by square brackets, while intramolecular G-quadruplexes and substrate DNA are indicated by arrows.