Figure 4.

G-quadruplex formation in long dsDNA carrying G-quadruplex-forming sequence from the NRAS gene examined by hydrolysis with mung bean nuclease (MBN) and S1 nuclease. DNA labeled at the 5′-end of the C-rich strand with a FAM (asterisk) was subjected to heat denaturation/renaturation in 150 mM K⁺, 40% (w/v) PEG 200 solution, then followed by hydrolysis with the indicated nuclease before denaturing gel electrophoresis. The single-stranded region opposite to the G-quadruplex is susceptible to the attack of the two nucleases.