Figure 5: FWHM of the x-ray diffraction radial intensity peaks from the arrays of DNA structures: Symbols and structures are the same as in Fig. 4a,b.
From: X-ray characterization of mesophases of human telomeric G-quadruplexes and other DNA analogues
In the less-ordered phases (Φdc), packing disorder decreases with increasing osmotic pressure for all structures. Further compression leads to Φdc → Φoc transitions with discontinuous changes in the packing order in duplex and GMP-quadruplex arrays, which occur concurrently with discontinuous changes in the packing densities (shown in Fig. 4a,b). The latter is not observed in the 22-mer HT-quadruplex arrays (discussed in the text). Phase-coexistence is shown only for the TG4T-quadruplex (shaded area). Phase-coexistence is observed over significantly narrower ranges of osmotic pressures for the duplex and GMP-quadruplex compared with the TG4T-quadruplex. The error in the determination of FWHM is as big as ≈0.1 nm−1 in the case of broad Gaussian peaks (in the disordered phases). The errors in FWHM are smaller for the sharp Lorentzian peaks in the ordered phases (see SI Appendix).
