Nanodisc Explained

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.

MSP nanodisc

The original nanodisc was produced by apoA1-derived MSPs from 2002.^[3] The size and stability of these discs depend on the size of these proteins, which can be adjusted by truncation and fusion. In general, MSP1 proteins consist of one repeat, and MSP2s are double-sized.^{[7] [8]}

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.

Synthetic/Native nanodisc

Another way to mimic the native lipid membrane are synthetic polymers. Styrene-maleic acid co-polymers (SMAs)^{[12] [13]} called SMALPs or Lipodisq and Diisobutylene-maleic acid (DIBMA)^[14] are such synthetic polymers (DIBMALPs). They can solubilize membrane proteins directly from cells or raw extract. They also have been used to study the lipid composition of several organisms.^{[15] [16] [17]} It was discovered that all synthetic polymers which contained a styrene and maleic acid group can solubilize proteins.^[18] These SMA nanoparticles have also been tested as possible drug delivery vehicle^[19] and for the study of folding, post-translational modifications and lipid interactions of membrane proteins by native mass spectrometry.^[20]

External links

• Nanodisc Technology from the Stephen Sligar laboratory
• Assembled nanodiscs for application with cell-free lysates
• HDL and Nanodiscs an overview of nanodisc technology at UIUC
• Phospholipid Bilayer Nanodiscs A summary from the Atkins lab at the University of Washington
• Purchase the MSP The plasmid for the MSP is available from AddGene
• SMA native nanodiscs website International research community website using SMA or other polymers (DIBMA for e.g.) as an alternative to conventional detergents and synthetic lipid environment found in MSP-Nanodisc.

Notes and References

1. Liszewski K . 1 October 2015. Dissecting the Structure of Membrane Proteins. Genetic Engineering & Biotechnology News. 35. 17. 16–18, 21. Nanodiscs are self-assembling nanoscale phospholipid bilayers that are stabilized using engineered membrane scaffold proteins.. 10.1089/gen.35.07.09.
2. Anada. Chiharu. Ikeda. Keisuke. Egawa. Ayako. Fujiwara. Toshimichi. Nakao. Hiroyuki. Nakano. Minoru. April 2021. Temperature- and composition-dependent conformational transitions of amphipathic peptide–phospholipid nanodiscs. Journal of Colloid and Interface Science. 588. 522–530. 10.1016/j.jcis.2020.12.090. 33429348. 0021-9797.
3. Bayburt TH, Grinkova YV, Sligar SG . 10.1021/nl025623k . Self-Assembly of Discoidal Phospholipid Bilayer Nanoparticles with Membrane Scaffold Proteins . Nano Letters . 2 . 8 . 853–856 . 2002 . 2002NanoL...2..853B .
4. Bayburt TH, Sligar SG . Membrane protein assembly into Nanodiscs . FEBS Letters . 584 . 9 . 1721–7 . May 2010 . 19836392 . 4758813 . 10.1016/j.febslet.2009.10.024 .
5. Skar-Gislinge N, Simonsen JB, Mortensen K, Feidenhans'l R, Sligar SG, Lindberg Møller B, Bjørnholm T, Arleth L . 6 . Elliptical structure of phospholipid bilayer nanodiscs encapsulated by scaffold proteins: casting the roles of the lipids and the protein . Journal of the American Chemical Society . 132 . 39 . 13713–22 . October 2010 . 20828154 . 4120756 . 10.1021/ja1030613 .
6. Denisov IG, Sligar SG . Cytochromes P450 in nanodiscs . Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics . 1814 . 1 . 223–9 . January 2011 . 20685623 . 2974961 . 10.1016/j.bbapap.2010.05.017 .
7. Denisov IG, Grinkova YV, Lazarides AA, Sligar SG . Directed self-assembly of monodisperse phospholipid bilayer Nanodiscs with controlled size . Journal of the American Chemical Society . 126 . 11 . 3477–87 . March 2004 . 15025475 . 10.1021/ja0393574 .
8. Grinkova YV, Denisov IG, Sligar SG . Engineering extended membrane scaffold proteins for self-assembly of soluble nanoscale lipid bilayers . Protein Engineering, Design & Selection . 23 . 11 . 843–8 . November 2010 . 20817758 . 2953958 . 10.1093/protein/gzq060 .
9. Midtgaard SR, Pedersen MC, Kirkensgaard JJ, Sørensen KK, Mortensen K, Jensen KJ, Arleth L . Self-assembling peptides form nanodiscs that stabilize membrane proteins . Soft Matter . 10 . 5 . 738–52 . February 2014 . 24651399 . 10.1039/c3sm51727f .
10. Larsen AN, Sørensen KK, Johansen NT, Martel A, Kirkensgaard JJ, Jensen KJ, Arleth L, Midtgaard SR . 6 . Dimeric peptides with three different linkers self-assemble with phospholipids to form peptide nanodiscs that stabilize membrane proteins . Soft Matter . 12 . 27 . 5937–49 . July 2016 . 27306692 . 10.1039/c6sm00495d . free . 2016SMat...12.5937L .
11. Kondo H, Ikeda K, Nakano M . Formation of size-controlled, denaturation-resistant lipid nanodiscs by an amphiphilic self-polymerizing peptide . Colloids and Surfaces. B, Biointerfaces . 146 . 423–30 . October 2016 . 27393815 . 10.1016/j.colsurfb.2016.06.040 .
12. Bada Juarez JF, Harper AJ, Judge PJ, Tonge SR, Watts A . From polymer chemistry to structural biology: The development of SMA and related amphipathic polymers for membrane protein extraction and solubilisation . Chemistry and Physics of Lipids . 221 . 167–175 . July 2019 . 30940445 . 10.1016/j.chemphyslip.2019.03.008 .
13. Knowles TJ, Finka R, Smith C, Lin YP, Dafforn T, Overduin M . Membrane proteins solubilized intact in lipid containing nanoparticles bounded by styrene maleic acid copolymer . Journal of the American Chemical Society . 131 . 22 . 7484–5 . June 2009 . 19449872 . 10.1021/ja810046q .
14. Oluwole AO, Klingler J, Danielczak B, Babalola JO, Vargas C, Pabst G, Keller S . Formation of Lipid-Bilayer Nanodiscs by Diisobutylene/Maleic Acid (DIBMA) Copolymer . Langmuir . 33 . 50 . 14378–14388 . December 2017 . 29160078 . 10.1021/acs.langmuir.7b03742 .
15. Lavington S, Watts A . Lipid nanoparticle technologies for the study of G protein-coupled receptors in lipid environments . Biophysical Reviews . 12 . 6 . 1287–1302 . November 2020 . 33215301 . 10.1007/s12551-020-00775-5 . 7755959 . free .
16. Barniol-Xicota M, Verhelst SH . Lipidomic and in-gel analysis of maleic acid co-polymer nanodiscs reveals differences in composition of solubilized membranes . Communications Biology . 4 . 1 . 218 . February 2021 . 33594255 . 10.1038/s42003-021-01711-3 . 7886889 . free .
17. Bada Juarez JF, O'Rourke D, Judge PJ, Liu LC, Hodgkin J, Watts A . Lipodisqs for eukaryote lipidomics with retention of viability: Sensitivity and resistance to Leucobacter infection linked to C.elegans cuticle composition . Chemistry and Physics of Lipids . 222 . 51–58 . August 2019 . 31102583 . 10.1016/j.chemphyslip.2019.02.005 .
18. Web site: Diisobutylene-maleic acid (DIBMA). Cube Biotech. en-GB. 2019-02-21.
19. Torgersen ML, Judge PJ, Bada Juarez JF, Pandya AD, Fusser M, Davies CW, Maciejewska MK, Yin DJ, Maelandsmo GM, Skotland T, Watts A, Sandvig K . 6 . Physicochemical Characterization, Toxicity and In Vivo Biodistribution Studies of a Discoidal, Lipid-Based Drug Delivery Vehicle: Lipodisq Nanoparticles Containing Doxorubicin . Journal of Biomedical Nanotechnology . 16 . 4 . 419–431 . April 2020 . 32970975 . 10.1166/jbn.2020.2911 . 10852/85267 . free .
20. Hoi KK, Bada Juarez JF, Judge PJ, Yen HY, Wu D, Vinals J, Taylor GF, Watts A, Robinson CV . 6 . Detergent-free Lipodisq Nanoparticles Facilitate High-Resolution Mass Spectrometry of Folded Integral Membrane Proteins . Nano Letters . March 2021 . 21 . 7 . 2824–2831 . 33787280 . 8050825 . 10.1021/acs.nanolett.0c04911 .