Nanodiscs versus Macrodiscs for NMR of Membrane Proteins

It is challenging to find membrane mimics that stabilize the native structures, dynamics, and functions of membrane proteins. In a recent advance, nanodiscs have been shown to provide a bilayer environment compatible with solution NMR. We show that increasing the lipid to belt peptide ratio expands their diameter, slows their reorientation rate, and allows the protein-containing discs to be aligned in a magnetic field for oriented sample solid-state NMR. The spectroscopic properties of membrane proteins with one to seven transmembrane helices in q = 0.1 isotropic bicelles, similar to 10 nm diameter isotropic nanodiscs, similar to 30 nm diameter magnetically aligned macrodiscs, and q = 5 magnetically aligned bicelles are compared.