Amphipols (a portmanteau of amphiphilicpolymers) are a class of amphiphilic polymers designed to keep membrane proteins soluble in water without the need for detergents, which are traditionally used to this end but tend to be denaturing.[1] Amphipols adsorb onto the hydrophobic transmembrane surface of membrane proteins thanks to their hydrophobic moieties and keep the complexes thus formed water-soluble thanks to the hydrophilic ones.[2] Amphipol-trapped membrane proteins are, as a rule, much more stable than detergent-solubilized ones, which facilitates their study by most biochemical and biophysical approaches.[3][4][5] Amphipols can be used to fold denatured membrane proteins to their native form[6][7] and have proven particularly precious in the field of single-particle electron cryo-microscopy (cryo-EM; see e.g.[8][9]).The properties and uses of amphipols and other non-conventional surfactants are the subject of a book by Jean-Luc Popot.[10]
^ Popot, J.-L., et al. (2011) Amphipols from A to Z. Annu. Rev. Biophys.40:379-408.
^Zoonens, M., Popot, J.-L. (2014) Amphipols for each season. J. Membr. Biol.247:759-796.
^Popot, J.-L. (2018) Membrane proteins in aqueous solutions: From detergents to amphipols. Springer, New York, in the press.
^Pocanschi, C.L., Dahmane, T., Gohon, Y., Rappaport, F., Apell, H.-J., Kleinschmidt, J.H., Popot, J.-L. (2006) Amphipathic polymers: tools to fold integral membrane proteins to their active form. Biochemistry45:13954-13961.
^Dahmane, T., Damian, M., Mary, S., Popot, J.-L., Banères, J.-L. (2009) Amphipol-assisted in vitro folding of G protein-coupled receptors. Biochemistry48:6516-6521.
^Althoff, T., Mills, D.J., Popot, J.-L., Kühlbrandt, W. (2011) Assembly of electron transport chain components in bovine mitochondrial supercomplex I1III2IV1. EMBO J.30:4652-4664.
^Liao, M., Cao, E., Julius, D., Cheng, Y. (2013) Structure of the TRPV1 ion channel determined by electron cryo-microscopy. Nature504:107-112.
^Popot, J.-L. (2018) Membrane proteins in aqueous solutions. From detergents to amphipols. Springer, New York, xxv + 708 p.