Localization of MN“II”-oxidizing activity and the putative multicopper oxidase, MnxG, to the exosporium of the marine Bacillus sp. Strain SG-1

Chris A. Francis, Karen L. Casciotti, Bradley M. Tebo

Research output: Contribution to journalArticle

74 Scopus citations

Abstract

Dormant spores of the marine Bacillus sp. strain SG-1 catalyze the oxidation of manganese“II”, thereby becoming encrusted with insoluble Mn“III, IV” oxides. In this study, it was found that the Mn“II”-oxidizing activity could be removed from SG-1 spores using a French press and recovered in the supernatant following centrifugation of the spores. Transmission electron microscopy of thin sections of SG-1 spores revealed that the ridged outermost layer was removed by passage through the French press, leaving the remainder of the spore intact. Comparative chemical analysis of this layer with the underlying spore coats suggested that this outer layer is chemically distinct from the spore coat. Taken together, these results indicate that this outer layer is an exosporium. Previous genetic analysis of strain SG-1 identified a cluster of genes involved in Mn“II” oxidation, the mnx genes. The product of the most downstream gene in this cluster, MnxG, appears to be a multicopper oxidase and is essential for Mn“II” oxidation. In this study, MnxG was overexpressed in Escherichia coli and used to generate polyclonal antibodies. Western blot analysis demonstrated that MnxG is localized to the exosporium of wild-type spores but is absent in the non-oxidizing spores of transposon mutants within the mnx gene cluster. To our knowledge, Mn“II” oxidation is the first oxidase activity, and MnxG one of the first gene products, ever shown to be associated with an exosporium.

Original languageEnglish (US)
Pages (from-to)450-456
Number of pages7
JournalArchives of Microbiology
Volume178
Issue number6
DOIs
StatePublished - Jan 1 2002

Keywords

  • Bacillus
  • Exosporium
  • MnxG
  • Mn“II” oxidation
  • Multicopper oxidase
  • Spores

ASJC Scopus subject areas

  • Microbiology
  • Biochemistry
  • Molecular Biology
  • Genetics

Fingerprint Dive into the research topics of 'Localization of MN“II”-oxidizing activity and the putative multicopper oxidase, MnxG, to the exosporium of the marine Bacillus sp. Strain SG-1'. Together they form a unique fingerprint.

  • Cite this