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J Biol Chem. 2015 Mar 6;290(10):6457-69. doi: 10.1074/jbc.M114.613810. Epub 2015 Jan 13.

Functional amyloids keep quorum-sensing molecules in check.

Author information

1
From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and twseviour@ntu.edu.sg.
2
the Center for Microbial Communities, Aalborg University, 9220 Aalborg East, Denmark.
3
From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and.
4
the School of Biological Sciences (SBS), Nanyang Technological University, Singapore 637551, Singapore.
5
From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the School of Materials Science and Engineering (MSE), Nanyang Technological University, Singapore 639798.
6
the Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN), and.
7
the Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark.
8
From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the Department of International Health, Immunology and Microbiology, University of Copenhagen, 1165 Copenhagen, Denmark, and.
9
From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the Center for Microbial Communities, Aalborg University, 9220 Aalborg East, Denmark.
10
From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the Centre for Marine Bio-innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Mosman, New South Wales 2088, Australia.

Abstract

The mechanism by which extracellular metabolites, including redox mediators and quorum-sensing signaling molecules, traffic through the extracellular matrix of biofilms is poorly explored. We hypothesize that functional amyloids, abundant in natural biofilms and possessing hydrophobic domains, retain these metabolites. Using surface plasmon resonance, we demonstrate that the quorum-sensing (QS) molecules, 2-heptyl-3-hydroxy-4(1H)-quinolone and N-(3-oxododecanoyl)-l-homoserine lactone, and the redox mediator pyocyanin bind with transient affinity to functional amyloids from Pseudomonas (Fap). Their high hydrophobicity predisposes them to signal-amyloid interactions, but specific interactions also play a role. Transient interactions allow for rapid association and dissociation kinetics, which make the QS molecules bioavailable and at the same time secure within the extracellular matrix as a consequence of serial bindings. Retention of the QS molecules was confirmed using Pseudomonas aeruginosa PAO1-based 2-heptyl-3-hydroxy-4(1H)-quinolone and N-(3-oxododecanoyl)-l-homoserine lactone reporter assays, showing that Fap fibrils pretreated with the QS molecules activate the reporters even after sequential washes. Pyocyanin retention was validated by electrochemical analysis of pyocyanin-pretreated Fap fibrils subjected to the same washing process. Results suggest that QS molecule-amyloid interactions are probably important in the turbulent environments commonly encountered in natural habitats.

KEYWORDS:

Amyloid; Biofilm; Functional Amyloid; Pseudomonas; Pseudomonas aeruginosa (P. aeruginosa); Quorum Sensing

PMID:
25586180
PMCID:
PMC4358280
DOI:
10.1074/jbc.M114.613810
[Indexed for MEDLINE]
Free PMC Article

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