Figure 5.

Temperature dependence of the magnetic alignment of macro–nanodiscs by ¹⁴N NMR. Nitrogen-14 NMR spectra of flipped DMPC:SMA-QA macro–nanodiscs containing 1 mM YbCl₃ as a function of temperature. Macro–nanodiscs are isotropic (and unaligned, indicated by 0 kHz ¹⁴N quadrupole coupling) below the gel-to-liquid crystalline phase transition temperature (295 K) of DMPC lipids. Above the phase transition temperature (>300 K), the macro–nanodiscs align with the lipid bilayer normal parallel to the applied magnetic field direction in the presence of 1 mM YbCl₃, as revealed by the observed quadrupole splitting of 18.8 kHz. All of these NMR spectra were acquired using a Bruker 400 MHz NMR spectrometer.