@article{03d637b0ecbd413c880c036ed11149e4,
  title     = "The cation diffusion facilitator proteins MamB and MamM of Magnetospirillum gryphiswaldense have distinct and complex functions, and are involved in magnetite biomineralization and magnetosome membrane assembly",
  abstract  = "Magnetotactic bacteria form chains of intracellular membrane-enclosed, nanometre-sized magnetite crystals for navigation along the earth's magnetic field. The assembly of these prokaryotic organelles requires several specific polypeptides. Among the most abundant proteins associated with the magnetosome membrane of Magnetospirillum gryphiswaldense are MamB and MamM, which were implicated in magnetosomal iron transport because of their similarity to the cation diffusion facilitator family. Here we demonstrate that MamB and MamM are multifunctional proteins involved in several steps of magnetosome formation. Whereas both proteins were essential for magnetite biomineralization, only deletion of mamB resulted in loss of magnetosome membrane vesicles. MamB stability depended on the presence of MamM by formation of a heterodimer complex. In addition, MamB was found to interact with several other proteins including the PDZ1 domain of MamE. Whereas any genetic modification of MamB resulted in loss of function, site-specific mutagenesis within MamM lead to increased formation of polycrystalline magnetite particles. A single amino acid substitution within MamM resulted in crystals consisting of haematite, which coexisted with magnetite crystals. Together our data indicate that MamM and MamB have complex functions, and are involved in the control of different key steps of magnetosome formation, which are linked by their direct interaction.",
  author    = "Ren{\'e} Uebe and Katja Junge and Verena Henn and Gabriele Poxleitner and Emanuel Katzmann and Plitzko, \{J{\"u}rgen M.\} and Raz Zarivach and Takeshi Kasama and Gerhard Wanner and Mih{\'a}ly P{\'o}sfai and Lars B{\"o}ttger and Berthold Matzanke and Dirk Sch{\"u}ler",
  year      = "2011",
  month     = nov,
  day       = "1",
  doi       = "10.1111/j.1365-2958.2011.07863.x",
  language  = "English",
  volume    = "82",
  pages     = "818--835",
  journal   = "Molecular Microbiology",
  issn      = "0950-382X",
  publisher = "John Wiley and Sons Inc",
  number    = "4",
}

@article{09f2ab8e2acc4984af123df774b250e5,
  title     = "Deletion of a fur-like gene affects iron homeostasis and magnetosome formation in Magnetospirillum gryphiswaldense",
  abstract  = "Magnetotactic bacteria synthesize specific organelles, the magnetosomes, which are membrane-enveloped crystals of the magnetic mineral magnetite (Fe 3O4). The biomineralization of magnetite involves the uptake and intracellular accumulation of large amounts of iron. However, it is not clear how iron uptake and biomineralization are regulated and balanced with the biochemical iron requirement and intracellular homeostasis. In this study, we identified and analyzed a homologue of the ferric uptake regulator Fur in Magnetospirillum gryphiswaldense, which was able to complement a fur mutant of Escherichia coli. A fur deletion mutant of M. gryphiswaldense biomineralized fewer and slightly smaller magnetite crystals than did the wild type. Although the total cellular iron accumulation of the mutant was decreased due to reduced magnetite biomineralization, it exhibited an increased level of free intracellular iron, which was bound mostly to a ferritin-like metabolite that was found significantly increased in M{\"o}ssbauer spectra of the mutant. Compared to that of the wild type, growth of the fur mutant was impaired in the presence of paraquat and under aerobic conditions. Using a Fur titration assay and proteomic analysis, we identified constituents of the Fur regulon. Whereas the expression of most known magnetosome genes was unaffected in the fur mutant, we identified 14 proteins whose expression was altered between the mutant and the wild type, including five proteins whose genes constitute putative iron uptake systems. Our data demonstrate that Fur is a regulator involved in global iron homeostasis, which also affects magnetite biomineralization, probably by balancing the competing demands for biochemical iron supply and magnetite biomineralization.",
  author    = "Ren{\'e} Uebe and Birgit Voigt and Thomas Schweder and Dirk Albrecht and Emanuel Katzmann and Claus Lang and Lars B{\"o}ttger and Berthold Matzanke and Dirk Sch{\"u}ler",
  year      = "2010",
  month     = aug,
  day       = "1",
  doi       = "10.1128/JB.00319-10",
  language  = "English",
  volume    = "192",
  pages     = "4192--4204",
  journal   = "Journal of Bacteriology",
  issn      = "0021-9193",
  publisher = "American Society for Microbiology",
  number    = "16",
}

@inbook{ec705bf4364145cb95ffe5ec21b62848,
  title     = "Magnetite formation via membrane-bound ferritin and an iron(II) species at the cytoplasmic membrane and in magnetosomes of Magnetospirillum gryphiswaldense",
  abstract  = "Growth and cell fractions of the magnetic bacterium Magnetospirillum gryphiswaldense were studied by M{\"o}ssbauer spectroscopy. In isolated magnetosomes only magnetite particles were observed. The membrane fraction of Magnetospirillum gryphiswaldense contains a ferritin-like component and a Fe2+ species and also magnetite particles smaller than those observed in the magnetosomes fraction. In the cytosol only ferritin was identified.",
  author    = "B{\"o}ttger, \{L. H.\} and D. Faivre and D. Sch{\"u}ler and X. Trautwein and F. Matzanke",
  year      = "2010",
  doi       = "10.1088/1742-6596/217/1/012020",
  language  = "English",
  isbn      = "1742-6596",
  series    = "Journal of Physics: Conference Series",
  publisher = "Institute of Physics Publishing",
  booktitle = "Journal of Physics: Conference Series",
}