Nanodisc
From Wikipedia, the free encyclopedia
A nanodisc is a synthetic model membrane system which assists in the study of membrane proteins.[1] Nanodiscs are discoidal proteins in which a lipid bilayer is surrounded by molecules that are amphipathic molecules including proteins, peptides, and synthetic polymers.[2] It is composed of a lipid bilayer of phospholipids with the hydrophobic edge screened by two amphipathic proteins. These proteins are called membrane scaffolding proteins (MSP) and align in double belt formation.[3][4][5] Nanodiscs are structurally very similar to discoidal high-density lipoproteins (HDL) and the MSPs are modified versions of apolipoprotein A1 (apoA1), the main constituent in HDL. Nanodiscs are useful in the study of membrane proteins because they can solubilise and stabilise membrane proteins[6] and represent a more native environment than liposomes, detergent micelles, bicelles and amphipols.
The art of making nanodiscs has progressed past using only the MSPs and lipids to make particles, leading to alternative strategies like peptide nanodiscs that use simpler proteins and synthetic nanodiscs that do not need any proteins for stabilization.
Peptide nanodisc
In peptide nanodiscs, the lipid bilayer is screened by amphipathic peptides instead of two MSPs. Peptide nanodiscs are structurally similar to MSP nanodiscs and the peptides also align in a double belt. They can stabilise membrane proteins,[9] but have higher polydispersity and are structurally less stable than MSP nanodiscs. Recent studies, however, showed that dimerization[10] and polymerization[11] of the peptides make them more stable.