Expression of Fap amyloids in Pseudomonas aeruginosa, P. fluorescens, and P. putida results in aggregation and increased biofilm formation. Issue 3 (18th March 2013)

• Record Type: Journal Article
• Authors: Dueholm, Morten S.; Søndergaard, Mads T.; Nilsson, Martin; Christiansen, Gunna; Stensballe, Allan; Overgaard, Michael T.; Givskov, Michael; Tolker‐Nielsen, Tim; Otzen, Daniel E.; Nielsen, Per H.
• Is Part Of: MicrobiologyOpen. Volume 2:Issue 3(2013:Jun.)
• Page Start: 365
• Page End: 382
• Publication Date: 2013-03-18
• Subjects: Microbiology -- Periodicals; 579
• DOI: 10.1002/mbo3.81
• Languages: English
• ISSNs: 2045-8827

Abstract

<abstract abstract-type="main" xml:lang="en" id="mbo381-abs-0001"> <title>Abstract</title> <p>The <italic>fap</italic> operon, encoding functional amyloids in <italic>Pseudomonas</italic> (Fap), is present in most pseudomonads, but so far the expression and importance for biofilm formation has only been investigated for <italic>P. fluorescens</italic> strain UK4. In this study, we demonstrate the capacity of <italic>P. aeruginosa </italic>PAO1, <italic>P. fluorescens</italic> Pf‐5, and <italic>P. putida</italic> F1 to express Fap fibrils, and investigated the effect of Fap expression on aggregation and biofilm formation. The <italic>fap</italic> operon in all three <italic>Pseudomonas</italic> species conferred the ability to express Fap fibrils as shown using a recombinant approach. This Fap overexpression consistently resulted in highly aggregative phenotypes and in increased biofilm formation. Detailed biophysical investigations of purified fibrils confirmed FapC as the main fibril monomer and supported the role of FapB as a minor, nucleating constituent as also indicated by bioinformatic analysis. Bioinformatics analysis suggested FapF and FapD as a potential β‐barrel membrane pore and protease, respectively. Manipulation of the <italic>fap</italic> operon showed that FapA affects monomer composition of the final amyloid fibril, and that FapB is an amyloid protein, probably a nucleator for FapC polymerization. Our study highlights the <italic>fap</italic> operon as a molecular machine for functional amyloid formation.</p> </abstract>