FIGURE 6.

NPM1-C70 is able to promote the formation of G-quadruplex arrangement in unstructured oligos, whereas it does not unfold G-quadruplexes. A, not annealed c-MYC oligo (20 μm) in the absence (gray solid line) and presence of increasing amounts of NPM1-C70 (gray dots, black dots, and black solid line for 10, 20, and 30 μm, respectively); the red shift and increase in amplitude at 260 nm and the formation of a through at 240 are indicative of G-quadruplex formation. B, not annealed G10-loop oligo (20 μm) in the absence (gray solid line) or presence of increasing amounts of NPM1-C70 (gray dots, black dots, and black solid line for 70, 100, and 150 μm, respectively). C, spectra of c-MYC oligo (20 μm), pre-annealed in the presence of 100 mm NaCl, and incubated with increasing amounts of NPM1-C70 (same amounts as in panel A). D, same experiment as in panel C performed using the G10-loop (20 μm). Amounts of NPM1-C70 are the same as in panel B.