2. Academic Validation
  3. A saposin-lipoprotein nanoparticle system for membrane proteins

A saposin-lipoprotein nanoparticle system for membrane proteins

  • Nat Methods. 2016 Apr;13(4):345-51. doi: 10.1038/nmeth.3801.
Jens Frauenfeld 1,  Robin Löving 2,  Jean-Paul Armache 3,  Andreas F-P Sonnen 4 5,  Fatma Guettou 1,  Per Moberg 1,  Lin Zhu 2 6,  Caroline Jegerschöld 2 6,  Ali Flayhan 7,  John A G Briggs 4 5,  Henrik Garoff 2,  Christian Löw 1 7,  Yifan Cheng 3 8,  Pär Nordlund 1
Affiliations

Affiliations

  • 1 Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
  • 2 Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
  • 3 Keck Advanced Microscopy Laboratory, Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA.
  • 4 Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
  • 5 Molecular Medicine Partnership Unit, European Molecular Biology Laboratory-Universitätsklinikum Heidelberg, Heidelberg, Germany.
  • 6 School of Technology and Health, Royal Institute of Technology, Novum, Huddinge, Sweden.
  • 7 EMBL Hamburg, Hamburg, Germany.
  • 8 Howard Hughes Medical Institute, University of California San Francisco, San Francisco, California, USA.
PMID: 26950744 DOI: 10.1038/nmeth.3801
Abstract

A limiting factor in membrane protein research is the ability to solubilize and stabilize such proteins. Detergents are used most often for solubilizing membrane proteins, but they are associated with protein instability and poor compatibility with structural and biophysical studies. Here we present a saposin-lipoprotein nanoparticle system, Salipro, which allows for the reconstitution of membrane proteins in a lipid environment that is stabilized by a scaffold of saposin proteins. We demonstrate the applicability of the method on two purified membrane protein complexes as well as by the direct solubilization and nanoparticle incorporation of a viral membrane protein complex from the virus membrane. Our approach facilitated high-resolution structural studies of the Bacterial peptide transporter PeptTSo2 by single-particle cryo-electron microscopy (cryo-EM) and allowed us to stabilize the HIV envelope glycoprotein in a functional state.

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