Detergent-free purification of ABC (ATP-binding-cassette) transporters

Sonali Gulati, Mohammed Jamshad, Timothy Knowles, Kerrie A. Morrison, Rebecca Downing, Natasha Cant, Richard Collins, Jan B. Koenderink, Robert C Ford, Michael Overduin, Ian D. Kerr, Alice J Rothnie

Research output: Contribution to journalArticlepeer-review

105 Citations (Scopus)

Abstract

ABC (ATP-binding-cassette) transporters carry out many vital functions and are involved in numerous diseases, but study of the structure and function of these proteins is often hampered by their large size and membrane location. Membrane protein purification usually utilizes detergents to solubilize the protein from the membrane, effectively removing it from its native lipid environment. Subsequently, lipids have to be added back and detergent removed to reconstitute the protein into a lipid bilayer. In the present study, we present the application of a new methodology for the extraction and purification of ABC transporters without the use of detergent, instead, using a copolymer, SMA (polystyrene-co-maleic acid). SMA inserts into a bilayer and assembles into discrete particles, essentially solubilizing the membrane into small discs of bilayer encircled by a polymer, termed SMALPs (SMA lipid particles). We show that this polymer can extract several eukaryotic ABC transporters, P-glycoprotein (ABCB1), MRP1 (multidrug-resistance protein 1; ABCC1), MRP4 (ABCC4), ABCG2 and CFTR (cystic fibrosis transmembrane conductance regulator; ABCC7), from a range of different expression systems. The SMALP-encapsulated ABC transporters can be purified by affinity chromatography, and are able to bind ligands comparably with those in native membranes or detergent micelles. A greater degree of purity and enhanced stability is seen compared with detergent solubilization. The present study demonstrates that eukaryotic ABC transporters can be extracted and purified without ever being removed from their lipid bilayer environment, opening up a wide range of possibilities for the future study of their structure and function.
Original languageEnglish
Pages (from-to)269-278
Number of pages12
JournalBiochemical Journal
Volume461
Issue number2
Early online date26 Jun 2014
DOIs
Publication statusPublished - Jul 2014

Keywords

  • detergent
  • membrane protein
  • nanodisc
  • polymer
  • purification
  • solubilization

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