Nanodisc

A nanodisc is a synthetic model membrane system which assists in the study of membrane proteins. 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. Nanodiscs are structurally very similar to 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 and represent a more native environment than liposomes, detergent micelles, bicelles and amphipols. A nanodisc is a synthetic model membrane system which assists in the study of membrane proteins. 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. Nanodiscs are structurally very similar to 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 and represent a more native environment than liposomes, detergent micelles, bicelles and amphipols. 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, but have higher polydispersity and are structurally less stable than MSP nanodiscs. Recent studies, however, showed that dimerization and polymerization of the peptides make them more stable. MSP-Nanodiscs can stabilise proteins and offer membrane proteins a native bilayer. Another way to mimic the native lipid membrane are synthtetic polymers. Styrene-maleic acid co-polymers (SMAs) and Diisobutylene-maleic acid (DIBMA) are such synthetic polymers. They can solubilize membrane proteins directly from cells or raw extract. It was discovered that all synthetic polymers which contained a styrene and maleic acid group can solubilize proteins. Roos, C; Kai, L; Haberstock, S; Proverbio, D; Ghoshdastider, U; Ma, Y; Filipek, S; Wang, X; Dötsch, V; Bernhard, F (2014). 'High-Level Cell-Free Production of Membrane Proteins with Nanodiscs'. Cell-Free Protein Synthesis. Methods in Molecular Biology. 1118. pp. 109–30. doi:10.1007/978-1-62703-782-2_7. ISBN 978-1-62703-781-5. PMID 24395412. Roos, C; Kai, L; Proverbio, D; Ghoshdastider, U; Filipek, S; Dötsch, V; Bernhard, F (2013). 'Co-translational association of cell-free expressed membrane proteins with supplied lipid bilayers'. Molecular Membrane Biology. 30 (1): 75–89. doi:10.3109/09687688.2012.693212. PMID 22716775. Ritchie, T. K.; Grinkova, Y. V.; Bayburt, T. H.; Denisov, I. G.; Zolnerciks, J. K.; Atkins, W. M.; Sligar, S. G. (2009). 'Chapter 11 Reconstitution of Membrane Proteins in Phospholipid Bilayer Nanodiscs'. Methods in Enzymology Volume 464. Methods in Enzymology. 464. pp. 211–231. doi:10.1016/S0076-6879(09)64011-8. ISBN 9780123749697. PMC 4196316. PMID 19903557. Kijac, A.; Shih, A. Y.; Nieuwkoop, A. J.; Schulten, K.; Sligar, S. G.; Rienstra, C. M. (2010). 'Lipid−Protein Correlations in Nanoscale Phospholipid Bilayers Determined by Solid-State Nuclear Magnetic Resonance'. Biochemistry. 49 (43): 9190–9198. doi:10.1021/bi1013722. PMC 3136391. PMID 20804175. Bayburt, T. H.; Sligar, S. G. (2010). 'Membrane protein assembly into Nanodiscs'. FEBS Letters. 584 (9): 1721–1727. doi:10.1016/j.febslet.2009.10.024. PMC 4758813. PMID 19836392. Morrissey, J. H.; Pureza, V.; Davis-Harrison, R. L.; Sligar, S. G.; Rienstra, C. M.; Kijac, A. Z.; Ohkubo, Y. Z.; Tajkhorshid, E. (2009). 'Protein-membrane interactions: Blood clotting on nanoscale bilayers'. Journal of Thrombosis and Haemostasis. 7 (Suppl 1): 169–172. doi:10.1111/j.1538-7836.2009.03390.x. PMC 2839880. PMID 19630793.