The Diverse Structures and Functions of Surfactant Proteins

Schor, Marieke; Reid, Jack L.; MacPhee, Cait E.; Stanley‐Wall, Nicola R.

doi:10.1016/j.tibs.2016.04.009

“…S2) that the role for disulfide bond formation in modulating BslA activity is not linked with either protein stability or folding, but is instead associated with imparting new function through multimerization. This function is in contrast to the fungal hydrophobins, where disulfide bonds stabilize the structure of the protein (26), and is more analogous to the mechanism used to control activity of the von Willebrand factor during blood clotting (25). Previous bioinformatic analyses revealed that Firmicutes, including B. subtilis, limit the number of proteins that contain cysteine residues (27).…”

Section: Discussionmentioning

confidence: 99%

Bifunctionality of a biofilm matrix protein controlled by redox state

Arnaouteli

¹

,

Ferreira

²

,

Schor

³

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

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 bacteriumBacillus subtilisdepend 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.

show abstract

“…S2) that the role for disulfide bond formation in modulating BslA activity is not linked with either protein stability or folding, but is instead associated with imparting new function through multimerisation. This is in contrast to the fungal hydrophobins where disulfide bonds stabilize the structure of the protein (26) and is more analogous to the mechanism used to control activity of the von Willebrand factor (vWF) during blood clotting (25). Previous bioinformatic analyses reveal that Firmicutes, including B. subtilis, limit the number of proteins that contain cysteine residues (27).…”

Section: Bifunctionality Through Dimerisationmentioning

confidence: 99%

Bifunctionality of a biofilm matrix protein controlled by redox state

Arnaouteli

¹

,

Ferreira

²

,

Schor

³

et al. 2017

Preprint

Self Cite

View full text Add to dashboard Cite

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, but despite this 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 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, while 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.SignificanceThe biofilm matrix is a critical target in the hunt for novel strategies to destabilise or stabilise biofilms. Knowledge of the processes controlling matrix assembly is therefore an essential prerequisite to exploitation. Here we highlight that the complexity of the biofilm matrix is even higher than anticipated with one matrix component making two independent functional contributions to the community. The influence the protein exerts is dependent on the local environmental properties, providing another dimension to consider during analysis. These findings add to the evidence that bacteria can evolve multifunctional uses for the extracellular matrix components.

show abstract

“…Thus, there has been increasing interest in finding organic Pickering particles for both food products and medical applications (Lam et al, 2014, Dickinson, 2010. Alternatives include polymer microgel particles (Matsumiya and Murray, 2016), certain proteins that act almost as Janus particles like fungal (Wang et al, 2013, Burke et al, 2014 and bacterial (Schor et al, 2016) hydrophobins and other polymer particles. Note that all these particles may not be strictly considered as Pickering stabilizers in that they have some degree of flexibility/deformability, though even silica particles have been shown to sinter together on adsorption, leading to so-called armoured bubbles (Abkarian et al, 2013).…”

Section: Introductionmentioning

confidence: 99%