Direct preparation of giant proteo-liposomes by in vitro membrane protein synthesis

We investigated the direct constitution of membrane proteins into giant liposomes in cell-free (in vitro) protein synthesis. Giant liposomes were present in a translation reaction cocktail of a wheat germ cell-free protein translation system. Apo cytochrome b(5) (M) and its fusion proteins were synthesized and directly localized in the liposomes. After the translation reaction, the proteo-liposomes were isolated by simplified discontinuous density-gradient centrifugation. Apo cytochrome b5 conjugated dihydrofolate reductase (DHFR) was synthesized in the same procedure and the protein was directly displayed on the liposome surface. b5 acts as a hydrophobic tag for recruitment to the liposome surface. (c) 2007 Elsevier B.V. All rights reserved.