Amphipols: Polymers that keep membrane proteins soluble in aqueous solutions

Amphipols: Polymers that keep membrane proteins soluble in aqueous solutions

^*Centre National de la Recherche Scientifique Unité de Recherche Associée 278 and Université Paris VI, Ecole Supérieure de Physique et de Chimie Industrielles, 10 rue Vauquelin, F-75231 Paris Cedex 05, France; and ^†Centre National de la Recherche Scientifique Unité Propre de Recherche 9052, Institut de Biologie Physico-Chimique, 13 rue Pierre-et-Marie-Curie, F-75005 Paris, Cedex 05, France

Abstract

Amphipols are a new class of surfactants that make it possible to handle membrane proteins in detergent-free aqueous solution as though they were soluble proteins. The strongly hydrophilic backbone of these polymers is grafted with hydrophobic chains, making them amphiphilic. Amphipols are able to stabilize in aqueous solution under their native state four well-characterized integral membrane proteins: (i) bacteriorhodopsin, (ii) a bacterial photosynthetic reaction center, (iii) cytochrome b ₆ f, and (iv) matrix porin.

Footnotes

Pierre Joliot, Institut de Biologie Physico-Chimique, Paris, France
Abbreviations: AP, ammonium phosphate; BR, bacteriorhodopsin; cmc, critical micellar concentration; EPC, egg phosphatidylcholine; HG, Hecameg [6-O-(N-heptylcarbamoyl)-methyl-α-d-glucopyranoside]; LM, laurylmaltoside; MW, molecular weight; octyl-POE, octylpolyoxyethylene; OTG, octylthioglucoside; RC, reaction center.