Constructing artificial respiratory chain in polymer compartments: Insights into the interplay betweenbo3oxidase and the membrane

Significance Analogous to phospholipids, some polymers assemble into vesicles and can mimic cellular membranes. Apart from enabling compartmentalization in the context of artificial cells, amphiphiles may serve as interface for proteins. However, complex transmembrane proteins were reconstituted in polymers with limited success so far. We functionally integrated the proton pump bo 3 oxidase (part of the bacterial respiratory chain) in synthetic membranes made of PDMS- g -PEO and demonstrated lumen acidification. We provided mechanistic insights into the interplay between the protein and the (semi)synthetic membrane by measuring bending rigidity, lateral diffusion and disorder, proton permeability, and protein partitioning. Polymer and hybrid membranes displayed favorable properties for the construction of artificial cells such as membrane rearrangement, enhanced stability and fluidity, while keeping the compartments proton-tight.