Peptide nanodiscs: Versatile platforms for membrane protein functional reconstitution and structural studies: A...

Peptide nanodiscs have emerged as powerful membrane-mimetic platforms for the reconstitution and structural investigation of membrane proteins. Designed as alternatives to traditional scaffold proteins, these nanodiscs are assembled using short amphipathic peptides that stabilize a lipid bilayer patch in a discoidal form. This review highlights the fundamental design principles of nanodisc-forming peptides, including sequence composition, net charge, and amphipathic balance, which govern their self-assembly, assembly with lipids and structural stability of the resultant nanodiscs. We also discuss how physicochemical properties influence nanodisc size, lipid compatibility, and membrane protein incorporation. Beyond their favorable properties, such as chemical tunability, detergent-free conditions, and compatibility, peptide nanodiscs provide a near-native bilayer environment that is well-suited for studying membrane proteins. This review further covers NMR studies on membrane-bound mammalian cytochrome P450 enzymes and their redox partners (cytochrome b₅ and cytochrome P450 reductase) reconstituted in peptide nanodiscs. These studies highlight the capacity of peptide-based systems to stabilize protein-protein interactions and maintain functional electron transfer within a lipid environment. Additionally, detergent-free isolation and cryoEM characterization of diverse prokaryotic and eukaryotic membrane proteins in peptide nanodiscs are discussed. Collectively, these advancements underscore the growing utility of peptide nanodiscs in structural biology, mechanistic biochemistry, and membrane protein-targeted drug discovery.