title: Liposome chaperon in cell-free membrane protein synthesis: one-step preparation of KcsA-integrated liposomes and electrophysiological analysis by the planar bilayer method.
abstract: Chaperoning functions of liposomes were investigated using cell-free membrane protein synthesis. KcsA potassium channel-reconstituted liposomes were prepared directly using cell-free protein synthesis. In the absence of liposomes, all synthesized KcsA protein aggregated. In the presence of liposomes, however, synthesized KcsA spontaneously integrated into the liposome membrane. The KscA-reconstituted liposomes were transferred to the planar bilayer across a small hole in a thin plastic sheet and the channel function of KcsA was examined. The original electrophysiological activities, such as voltage- and pH-dependence, were observed. These results suggested that in cell-free membrane protein synthesis, liposomes act as chaperones, preventing aggregation and assisting in folding and tetrameric formation, thereby allowing full channel activity.
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan. akiyoshi@bio.polym.kyoto-u.ac.jp and Japan Science and Technology Agency (JST), The Exploratory Research for Advanced Technology (ERATO), Bio-nanotransporter Project, Katsura Int'tech Center, Katsura, Nishikyo-ku, Kyoto 615-8530, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ando
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan. akiyoshi@bio.polym.kyoto-u.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Akiyama
authors.affiliation: Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Okuno
authors.affiliation: Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan and Bio Photonics Laboratory, The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsu Nishi-ku Hamamatsu, Shizuoka 431-1202, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hirano
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka Kita-ku Okayama, Okayama 700-8530, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ide
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan. akiyoshi@bio.polym.kyoto-u.ac.jp and Japan Science and Technology Agency (JST), The Exploratory Research for Advanced Technology (ERATO), Bio-nanotransporter Project, Katsura Int'tech Center, Katsura, Nishikyo-ku, Kyoto 615-8530, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Sawada
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan. akiyoshi@bio.polym.kyoto-u.ac.jp.
authors.forename: Y
authors.initials: Y
authors.lastname: Sasaki
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan. akiyoshi@bio.polym.kyoto-u.ac.jp and Japan Science and Technology Agency (JST), The Exploratory Research for Advanced Technology (ERATO), Bio-nanotransporter Project, Katsura Int'tech Center, Katsura, Nishikyo-ku, Kyoto 615-8530, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Akiyoshi
mesh_terms: D055724:Electrophysiological Phenomena; D008081:Liposomes / Q000737:chemistry* / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018832:Molecular Chaperones / Q000737:chemistry*; D015221:Potassium Channels / Q000737:chemistry* / Q000378:metabolism; D014176:Protein Biosynthesis / Q000235:genetics*
chemical_list: D008081:Liposomes; D008565:Membrane Proteins; D018832:Molecular Chaperones; D015221:Potassium Channels