title: Origin of magnetosome membrane: proteomic analysis of magnetosome membrane and comparison with cytoplasmic membrane.
abstract: Prokaryotes are known to have evolved one or more unique organelles. Although several hypotheses have been proposed concerning the biogenesis of these intracellular components, the majority of these proposals remains unclear. Magnetotactic bacteria synthesize intracellular magnetosomes that are enclosed by lipid bilayer membranes. From the identification and characterization of several surface and transmembrane magnetosome proteins, we have postulated that magnetosomes are derived from the cytoplasmic membrane (CM). To confirm this hypothesis, a comparative proteomic analysis of the magnetosome membrane (MM) and CM of the magnetotactic bacterium, Magnetospirillum magneticum AMB-1, was undertaken. Based on the whole genome sequence of M. magneticum AMB-1, 78 identified MM proteins were also found to be prevalent in the CM, several of which are related to magnetosome biosynthesis, such as Mms13, which is tightly bound on the magnetite surface. Fatty acid analysis was also conducted, and showed a striking similarity between the CM and MM profiles. These results suggest that the MM is derived from the CM.
authors.affiliation: Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Tanaka
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Okamura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Arakaki
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tanaka
authors.forename: Haruko
authors.initials: H
authors.lastname: Takeyama
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsunaga
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000032:analysis* / Q000737:chemistry; D002853:Chromatography, Liquid; D003593:Cytoplasm / Q000737:chemistry* / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D007425:Intracellular Membranes / Q000737:chemistry* / Q000502:physiology*; D042201:Magnetospirillum / Q000737:chemistry / Q000502:physiology*; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000032:analysis* / Q000737:chemistry; D020543:Proteome / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008565:Membrane Proteins; D020543:Proteome