Sulfonated amphipols: Synthesis, properties, and applications

Authors

  • Tassadite Dahmane,,

    1. Laboratoire de Physico-Chimie Moléculaire des Membranes Biologiques, UMR 7099, CNRS and Université Paris-7, Institut de Biologie Physico-Chimique, CNRS IFR 550, 13 rue Pierre et Marie Curie, F-75005 Paris, France
    Current affiliation:
    1. Department of Biochemistry and Molecular Biophysics, Columbia University, 650 West 168th Street, 202 BB, New York, NY 10032, USA
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    • Tassadite Dahmane and Fabrice Giusti contributed equally to this work.

  • Fabrice Giusti,

    1. Laboratoire de Physico-Chimie Moléculaire des Membranes Biologiques, UMR 7099, CNRS and Université Paris-7, Institut de Biologie Physico-Chimique, CNRS IFR 550, 13 rue Pierre et Marie Curie, F-75005 Paris, France
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    • Tassadite Dahmane and Fabrice Giusti contributed equally to this work.

  • Laurent J. Catoire,

    1. Laboratoire de Physico-Chimie Moléculaire des Membranes Biologiques, UMR 7099, CNRS and Université Paris-7, Institut de Biologie Physico-Chimique, CNRS IFR 550, 13 rue Pierre et Marie Curie, F-75005 Paris, France
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  • Jean-Luc Popot

    Corresponding author
    1. Laboratoire de Physico-Chimie Moléculaire des Membranes Biologiques, UMR 7099, CNRS and Université Paris-7, Institut de Biologie Physico-Chimique, CNRS IFR 550, 13 rue Pierre et Marie Curie, F-75005 Paris, France
    • Laboratoire de Physico-Chimie Moléculaire des Membranes Biologiques, UMR 7099, CNRS and Université Paris-7, Institut de Biologie Physico-Chimique, CNRS IFR 550, 13 rue Pierre et Marie Curie, F-75005 Paris, France
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  • This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com

Abstract

Amphipols (APols) are amphiphatic polymers that keep membrane proteins (MPs) water-soluble. The best characterized and most widely used APol to date, A8-35, comprises a polyacrylate backbone grafted with octyl- and isopropylamine side chains. The nature of its hydrophilic moieties prevents its use at the slightly acidic pH that is desirable to slow down the rate of amide proton exchange in solution NMR studies. We describe here the synthesis and properties of pH-insensitive APols obtained by replacing isopropyles with taurine. Sulfonated APols (SAPols) can be used to trap MPs in the form of small complexes, to stabilize them, and to keep them water-soluble even at low pH. [15N,1H]-transverse relaxation-optimized spectroscopy NMR spectra obtained at pH 6.8 of a bacterial outer MP folded in SAPols show that the protein is correctly folded. The spectra have a resolution similar to that achieved with A8-35 and reveal water-exposed amide and indole protons whose resonance peaks are absent at pH 8.0. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 811–823, 2011.

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