title: Magnetospirillum magneticum AMB-1 peroxiredoxins contribute to the aerotolerance and genetic stability of the genomic magnetosome island.
abstract: The magnetotactic bacterium Magnetospirillum magneticum AMB-1 can grow at variable oxygen concentrations, although the intracellular magnetic structures, magnetosomes, are only synthesized under microaerobic or anaerobic conditions. Three members of the peroxiredoxin family were identified in M. magneticum AMB-1. All purified recombinant proteins displayed thiol-dependent peroxidase activities. Allelic replacement mutagenesis revealed that, although the absence of the three peroxidase genes had no effect on either the growth or the formation of magnetosome under anaerobic conditions, the growth of mutants was compromised in an aerobic culture. Moreover, an accelerated loss in the genomic 'magnetosome island' (MAI) was observed in the null mutants cultured in the presence of oxygen. Taken together, these data suggest that the thiol-peroxidases identified act as key antioxidants in magnetotactic bacteria and, as a result, contribute to maintaining their capacity to synthesize magnetosome by shielding the genetic stability of the genomic MAI in adaptation to constant physiological change and stress.
authors.affiliation: The State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Ge
authors.forename: Kuan
authors.initials: K
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Bo
authors.forename: Yanbo
authors.initials: Y
authors.lastname: Kou
authors.forename: Weifeng
authors.initials: W
authors.lastname: Liu
authors.forename: Guanjun
authors.initials: G
authors.lastname: Chen
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D044404:Genomic Islands; D055944:Magnetosomes / Q000378:metabolism / Q000502:physiology*; D042201:Magnetospirillum / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D005810:Multigene Family; D054464:Peroxiredoxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020539:Sequence Analysis, Protein; D017384:Sequence Deletion
chemical_list: D000975:Antioxidants; D054464:Peroxiredoxins