Functionalized Amphipols: A Versatile Toolbox Suitable for Applications of Membrane Proteins in Synthetic Biology

Abstract

Amphipols are amphipathic polymers that stabilize membrane proteins isolated from their native membrane. They have been functionalized with various chemical groups in the past years for protein labeling and protein immobilization. This large toolbox of functionalized amphipols combined with their interesting physico-chemical properties give opportunities to selectively add multiple functionalities to membrane proteins and to tune them according to the needs. This unique combination of properties makes them one of the most versatile strategies available today for exploiting membrane proteins onto surfaces for various applications in synthetic biology. This review summarizes the properties of functionalized amphipols suitable for synthetic biology approaches.

Amphipols for Each Season

“…They can be, for example, extensively diluted with APol-free buffer (Tribet et al 2009; Zoonens et al 2007), washed with surfactant-free buffer after adsorption onto solid supports (Charvolin et al 2009; Della Pia et al 2014a, b; Giusti et al 2014a; Le Bon et al 2014a), or injected on a SEC column pre-equilibrated with surfactant-free buffer (Charvolin et al 2014; Gohon et al 2008; Zoonens et al 2007). Nevertheless, the APol layer can be easily displaced and exchanged upon exposure to an excess of competing surfactants, be they detergents (Damian et al 2012; Tribet et al 1997, 2009; Zoonens et al 2007), lipid vesicles (Nagy et al 2001), black lipid membranes (BLM) (Pocanschi et al 2006), lipidic three-dimensional (3D) phases (Polovinkin et al 2014b), cell plasma membranes (Popot et al 2011), or free APols (Tribet et al 1997; Zoonens et al 2007) (Fig.…”

“…Biol. provide more details and discussion about using APols for solution NMR studies of MPs (Planchard et al 2014), in synthetic biology (Della Pia et al 2014b), as a tool to manipulate biological membranes (Marie et al 2014), or for the study of specific classes of MPs (Huynh et al 2014; Mary et al 2014). A sixth one covers the important subject of the chemistry of APol labeling and functionalization (Le Bon et al 2014b).…”

“…Because direct interactions of MPs with solid surfaces tend to be denaturing, immobilization is usually mediated by a tag fused at one extremity of the protein chain, implying its genetic modification. Functionalized APols bearing affinity tags provide a very promising alternative for attaching MPs onto solid supports (Charvolin et al 2009) (reviewed by Della Pia et al 2014b). APol-mediated immobilization indeed presents many practical advantages:…”

Labeling and Functionalizing Amphipols for Biological Applications

“…5) so as to mediate MP immobilization onto avidin-, neutravidin- or streptavidin-coated solid supports (Charvolin et al 2009; Della Pia et al 2014a, b; Ferrandez et al 2014). Biotinylation was achieved either by reacting UAPol-NH 2 with an activated ester of biotin or by modifying PAA with an amino derivative of biotin during HMPAS.…”

“…Their fate following injection to mice was followed by fluorescence imaging, as well as that of FAPol rhod (Fernandez et al 2014). FAPol AF647 and FAPol NBD have also been used to visualize, by fluorescence microscopy, the adsorption of APol particles and MP/APol complexes carrying either a biotin or an oligo-nucleotide tag onto appropriately functionalized gold nanoparticles (Della Pia et al 2014a, b; Le Bon et al 2014). …”