Nanodisc preparation and characterization. (Top row) Schematic representation of the preparation of nanodiscs for solid-state NMR experiments, isotropic nanodiscs, and the alignment of macro–nanodiscs in the presence of an external magnetic field. (Bottom row) DMPC and SMA-QA chemical formulae, SEC chromatogram, TEM, and an illustration of flipped macro–nanodiscs in the presence of lanthanide ions.