Bifunctionality of a biofilm matrix protein controlled by redox state

Sofia Arnaouteli, Ana Sofia Ferreira, Marieke Schor, Ryan J. Morris, Keith M. Bromley, Jeanyoung Jo, Krista L. Cortez, Tetyana Sukhodub, Alan R. Prescott, Lars E.P. Dietrich, Cait E. MacPhee*, Nicola R. Stanley-Wall

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Biofilms are communities of microbial cells that are encapsulated within a self-produced polymeric matrix. The matrix is critical to the success of biofilms in diverse habitats; however, many details of the composition, structure, and function remain enigmatic. Biofilms formed by the Gram-positive bacterium Bacillus subtilis depend on the production of the secreted film-forming protein BslA. Here, we show that a gradient of electron acceptor availability through the depth of the biofilm gives rise to two distinct functional roles for BslA and that these roles can be genetically separated through targeted amino acid substitutions. We establish that monomeric BslA is necessary and sufficient to give rise to complex biofilm architecture, whereas dimerization of BslA is required to render the community hydrophobic. Dimerization of BslA, mediated by disulfide bond formation, depends on two conserved cysteine residues located in the C-terminal region. Our findings demonstrate that bacteria have evolved multiple uses for limited elements in the matrix, allowing for alternative responses in a complex, changing environment.

Original languageEnglish
Pages (from-to)E6184-E6191
Number of pages8
JournalProceedings of the National Academy of Sciences
Volume114
Issue number30
Early online date11 Jul 2017
DOIs
Publication statusPublished - 25 Jul 2017

Keywords

  • Bacillus subtilis
  • Biofilm matrix
  • BslA
  • Hydrophobicity
  • Redox

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