Biogenic manganese oxide nanoparticle formation by a multimeric multicopper oxidase Mnx

Christine A. Romano, Mowei Zhou, Yang Song, Vicki H. Wysocki, Alice C. Dohnalkova, Libor Kovarik, Ljiljana Paša-Tolić, Bradley Tebo

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Abstract

Bacteria that produce Mn oxides are extraordinarily skilled engineers of nanomaterials that contribute significantly to global biogeochemical cycles. Their enzyme-based reaction mechanisms may be genetically tailored for environmental remediation applications or bioenergy production. However, significant challenges exist for structural characterization of the enzymes responsible for biomineralization. The active Mn oxidase in Bacillus sp. PL-12, Mnx, is a complex composed of a multicopper oxidase (MCO), MnxG, and two accessory proteins, MnxE and MnxF. MnxG shares sequence similarity with other, structurally characterized MCOs. MnxE and MnxF have no similarity to any characterized proteins. The ∼200 kDa complex has been recalcitrant to crystallization, so its structure is unknown. Here, we show that native mass spectrometry defines the subunit topology and copper binding of Mnx, while high-resolution electron microscopy visualizes the protein and nascent Mn oxide minerals. These data provide critical structural information for understanding Mn biomineralization by such unexplored enzymes.

Original languageEnglish (US)
Article number746
JournalNature Communications
Volume8
Issue number1
DOIs
StatePublished - Dec 1 2017

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ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

Cite this

Romano, C. A., Zhou, M., Song, Y., Wysocki, V. H., Dohnalkova, A. C., Kovarik, L., Paša-Tolić, L., & Tebo, B. (2017). Biogenic manganese oxide nanoparticle formation by a multimeric multicopper oxidase Mnx. Nature Communications, 8(1), [746]. https://doi.org/10.1038/s41467-017-00896-8