Non-ionic amphiphilic homopolymers: synthesis, solution properties, and biochemical validation.
A novel type of nonionic amphipols for handling membrane proteins in detergent-free aqueous solutions has been obtained through free-radical homo-telomerization of an acrylamide-based monomer comprising a C(11) alkyl chain and two glucose moieties, using a thiol as transfer reagent. By controlling the thiol/monomer ratio, the number-average molecular weight of the polymers was varied from 8 to 63 kDa. Homopolymeric nonionic amphipols were found to be highly soluble in water and to self-organize, within a large concentration range, into small, compact particles of ~6 nm diameter with a narrow size distribution, regardless of the molecular weight of the polymer. They proved able to trap and stabilize two test membrane proteins, bacteriorhodopsin from Halobium salinarum and the outer membrane protein X of Escherichia coli, under the form of small and well-defined complexes, whose size, composition, and shape were studied by aqueous size-exclusion chromatography, analytical ultracentrifugation, and small-angle neutron scattering. As shown in a companion paper, nonionic amphipols can be used for membrane protein folding, cell-free synthesis, and solution NMR studies (Bazzacco et al. 2012, Biochemistry, DOI: 10.1021/bi201862v).
Université d'Avignon et des Pays de Vaucluse, Equipe Chimie Bioorganique et Systèmes Amphiphiles, Avignon, France.
K Shivaji
KS
Sharma
Grégory
G
Durand
Frank
F
Gabel
Paola
P
Bazzacco
Christel
C
Le Bon
Emmanuelle
E
Billon-Denis
Laurent J
LJ
Catoire
Jean-Luc
JL
Popot
Christine
C
Ebel
Bernard
B
Pucci
D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry; D001436:Bacteriorhodopsins / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry; D019617:Halobacterium salinarum / Q000737:chemistry; D006867:Hydrolases / Q000737:chemistry; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D033363:Neutron Diffraction; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry*; D055550:Protein Stability; D053838:Scattering, Small Angle; D012996:Solutions; D013501:Surface-Active Agents / Q000138:chemical synthesis* / Q000737:chemistry*
D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D011108:Polymers; D012996:Solutions; D013501:Surface-Active Agents; C482905:OmpX protein, E coli; D001436:Bacteriorhodopsins; D006867:Hydrolases