Membrane proteins: is the future disc shaped?

Biochem Soc Trans. 2016 Aug 15;44(4):1011-8. doi: 10.1042/BST20160015.


The use of styrene maleic acid lipid particles (SMALPs) for the purification of membrane proteins (MPs) is a rapidly developing technology. The amphiphilic copolymer of styrene and maleic acid (SMA) disrupts biological membranes and can extract membrane proteins in nanodiscs of approximately 10 nm diameter. These discs contain SMA, protein and membrane lipids. There is evidence that MPs in SMALPs retain their native structures and functions, in some cases with enhanced thermal stability. In addition, the method is compatible with biological buffers and a wide variety of biophysical and structural analysis techniques. The use of SMALPs to solubilize and stabilize MPs offers a new approach in our attempts to understand, and influence, the structure and function of MPs and biological membranes. In this review, we critically assess progress with this method, address some of the associated technical challenges, and discuss opportunities for exploiting SMA and SMALPs to expand our understanding of MP biology.

Keywords: SMA; SMALPs; biophysical studies; detergent-free; membrane proteins; protein purification; styrene maleic acid.

Publication types

  • Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Membrane / chemistry*
  • Cell Membrane / ultrastructure
  • Lipid Bilayers / chemistry*
  • Maleates / chemistry
  • Membrane Lipids / chemistry*
  • Membrane Proteins / chemistry*
  • Membrane Proteins / isolation & purification
  • Microscopy, Electron
  • Particle Size
  • Polystyrenes / chemistry
  • Protein Stability
  • Solubility


  • Lipid Bilayers
  • Maleates
  • Membrane Lipids
  • Membrane Proteins
  • Polystyrenes
  • styrene-maleic acid polymer