title: A novel and mild isolation procedure of chlorosomes from the green sulfur bacterium Chlorobaculum tepidum.
abstract: In this article, we developed a new and mild procedure for the isolation of chlorosomes from a green sulfur bacterium Chlorobaculum tepidum. In this procedure, Fenna-Matthews-Olson (FMO) protein was released by long cold treatment (6°C) of cells under the presence of a chaotrope (2 M NaSCN) and 0.6 M sucrose. Chlorosomes were released by an osmotic shock of the cold-treated cells after the formation of spheroplasts without mechanical disruption. Chlorosomes were finally purified by a sucrose step-wise density gradient centrifugation. We obtained two samples with different density (20 and 23% sucrose band, respectively) and compared them by SDS-PAGE, absorption spectroscopy at 80 K, fluorescence and CD spectroscopy at room temperature. Cells whose absorption maximum was longer than 750 nm yielded higher amount of the 20% sucrose fraction than those having an absorption maximum shorter than 750 nm.
authors.affiliation: Department of Biology, Tokyo Metropolitan University, Tokyo, 192-0397, Japan. tokita-seiji@tmu.ac.jp
authors.forename: Seiji
authors.initials: S
authors.lastname: Tokita
authors.forename: Keizo
authors.initials: K
authors.lastname: Shimada
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Watabe
authors.forename: Katsumi
authors.initials: K
authors.lastname: Matsuura
authors.forename: Mamoru
authors.initials: M
authors.lastname: Mimuro
mesh_terms: D001426:Bacterial Proteins / Q000302:isolation & purification; D001671:Biochemistry / Q000379:methods*; D002499:Centrifugation, Density Gradient; D019414:Chlorobi / Q000187:drug effects / Q000378:metabolism*; D002942:Circular Dichroism; D004735:Energy Transfer / Q000187:drug effects; D045342:Light-Harvesting Protein Complexes / Q000302:isolation & purification; D015388:Organelles / Q000187:drug effects / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000494:pharmacology; D015203:Reproducibility of Results; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; C086320:FMO bacteriochlorophyll protein, Bacteria; D045342:Light-Harvesting Protein Complexes; D011092:Polyethylene Glycols