title: Assembly of a photosynthetic reaction center with ABA tri-block polymersomes: highlights on protein localization.
abstract: The reconstitution of the integral membrane protein photosynthetic reaction center (RC) in polymersomes, i.e. artificial closed vesicles, was achieved by the micelle-to-vesicle transition technique, a very mild protocol based on size exclusion chromatography often used to drive the incorporation of proteins contemporarily to liposome formation. An optimized protocol was used to successfully reconstitute the protein in a fully active state in polymersomes formed by the tri-block copolymers PMOXA22-PDMS61-PMOXA22. The RC is very sensitive to its solubilizing environment and was used to probe the positioning of the protein in the vesicles. According to charge-recombination experiments and to the enzymatic activity assay, the RC is found to accommodate in the PMOXA22 region of the polymersome, facing the water bulk solution, rather than in the PDMS61 transmembrane-like region. Furthermore, polymersomes were found to preserve protein integrity efficiently as the biomimetic lipid bilayers but show a much longer temporal stability than lipid based vesicles.
authors.affiliation: Chemistry Department, Università degli Studi di Bari "Aldo Moro", via Orabona 4, 70125 Bari, Italy.
authors.forename: R R
authors.initials: RR
authors.lastname: Tangorra
authors.forename: A
authors.initials: A
authors.lastname: Operamolla
authors.forename: F
authors.initials: F
authors.lastname: Milano
authors.forename: O
authors.initials: O
authors.lastname: Hassan Omar
authors.forename: J
authors.initials: J
authors.lastname: Henrard
authors.forename: R
authors.initials: R
authors.lastname: Comparelli
authors.forename: F
authors.initials: F
authors.lastname: Italiano
authors.forename: A
authors.initials: A
authors.lastname: Agostiano
authors.forename: V
authors.initials: V
authors.lastname: De Leo
authors.forename: R
authors.initials: R
authors.lastname: Marotta
authors.forename: A
authors.initials: A
authors.lastname: Falqui
authors.forename: G M
authors.initials: GM
authors.lastname: Farinola
authors.forename: M
authors.initials: M
authors.lastname: Trotta
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008567:Membranes, Artificial; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry*; D021381:Protein Transport; D012242:Rhodobacter sphaeroides / Q000201:enzymology
chemical_list: D008567:Membranes, Artificial; D045322:Photosynthetic Reaction Center Complex Proteins; D011108:Polymers