Fig. 2: Characterization of fZ-motif.
From: A folding motif formed with an expanded genetic alphabet
a, Structural influence of pH on reverse skinny C:C and Z:Z pair formation in various charge conditions. b, The effect of pH on ThT fluorescence when intercalated into C-rich sequences able to form the i-motif via dC:dC+ pairing. c, The impact of pH on ThT fluorescence when intercalated into dZ-rich sequences able to form the fZ-motif via dZ:dZ− pairing. There were n = 5 independent runs; error bars in b and c represent mean values ± s.d. The blue shaded areas represent the DNA forming the motif structure. d–f, DNA samples analysed by non-denaturing polyacrylamide gel electrophoresis (20%) in 2-(N-morpholino)ethanesulfonic acid (MES) (d), TS (e) and TBE (f) buffers. Left lane: T10, T20 and T30 oligonucleotides. Lane 1, i-motif; lane 2, C-control; lane 3, fZ-motif; lane 4, Z-control1; lane 5, Z-control2; lane 6, Z-control3. The gels were stained using the Stains-All dye. g, Photographs of fluorescence of DNA samples (1 μM) in 100 mM phosphate buffer with pHs ranging from 6 to 11 at 25 °C. h,i, Melting peaks of ZZZ-FQ (h) and Z-control4-FQ (i) reveal temperature responses across pHs 6 to 9 in phosphate buffer. j,k, Absorption spectra of dZ nucleoside (j) and ZZZ oligo (k) in phosphate buffer across pHs 5–9. l,m, Circular dichroism (CD) spectra compare ZZZ oligo (l) and i-motif (m) sequences, highlighting structural insights across pHs 6–9 in phosphate buffer.
