Table 1.
Oligonucleotide sequences used in this study.a
Figure 1.
G-repeat expansion RNA and DNA form G-quadruplexes in the presence of potassium.
UV Circular Dichroism spectra of (A) r(G4C2)4, (B) r(C4G2)4, (C) d(G4C2)4, and (D) d(C4G2)4 in 25 mM Tris, pH 7.5, in the presence of either 0 mM or 100 mM KCl.
Figure 2.
G-repeat expansion RNA and DNA bind heme.
UV-visible spectroscopy of fixed concentrations of heme (0.5 µM) titrated and equilibrated with progressively increasing concentrations of DNA/RNA. (A) d(G4C2)4, (B) r(G4C2)4, (C) d(C4G2)4, (D) r(C4G2)4, (E) CatG4. Panel F shows plots of A404nm from each of the plots shown in (A)–(E), as functions of the DNA/RNA concentration.
Figure 3.
c9orf72 repeat DNA And RNA catalyze peroxidase reactions.
kobs values for peroxidation reactions made up of 10 µM DNA/RNA, 0.1 µM heme, 1 mM ABTS and varied hydrogen peroxide concentrations from 0-5 mM. Panel A reactions were carried out in NH4-HEPES buffer (40 mM HEPES, pH 8.0, 20 mM potassium chloride, 1% N,N-dimethylformamide, 0.05% Triton X-100); and, Panel B reactions were carried out in Tris buffer (25 mM Tris-Cl, pH 8.0, 20 mM potassium chloride, 1% N,N-dimethylformamide, 0.05% Triton X-100).
Figure 4.
c9orf72 repeat DNA and RNA catalyze oxidase reactions with NADH and ascorbate.
(A) A photographic record of the oxidase activity of different DNA/RNA solutions in the presence of heme. Amplex Red oxidation to resorufin produces an intense red color. Each solution containing DNA/RNA (10 µM) and heme (1 µM) was incubated with 1 mM Amplex Red in the presence of NADH or Ascorbate (1 mM), the absence of a reductant or hydrogen peroxide (0.1 mM). (B) UV/Vis spectra for samples from panel A at ∼24 hrs, showing characteristic spectra for resorufin (lmax ∼570 nm).