Protein Engineering Reveals Mechanisms of Functional Amyloid Formation in Pseudomonas aeruginosa Biofilms

JOURNAL OF MOLECULAR BIOLOGY

卷:430

Article

Bleem, Alissa¹  Christiansen, Gunna²  Madsen, Daniel J.³  Maric, Hans⁴  Stromgaard, Kristian⁴  Bryers, James D.¹  Daggett, Valerie¹  Meyer, Rikke L.³  Otzen, Daniel E.³ 

[1] Univ Washington, Dept Bioengn, Seattle, WA 98195 USA

[2] Aarhus Univ, Dept Biomed Med Microbiol & Immunol, DK-8000 Aarhus C, Denmark

[3] Aarhus Univ, Interdisciplinary Nanosci Ctr iNANO, Dept Mol Biol & Genet, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark

[4] Univ Copenhagen, Dept Drug Design & Pharmacol, DK-2100 Copenhagen O, Denmark

关键词: protein aggregation;    bacterial amyloid;    extracellular matrix;    protein sequence analysis;    peptide microarray;   

DOI  :  10.1016/j.jmb.2018.06.043

来源: Elsevier

【 摘 要 】

Amyloids are typically associated with neurodegenerative diseases, but recent research demonstrates that several bacteria utilize functional amyloid fibrils to fortify the biofilm extracellular matrix and thereby resist antibiotic treatments. In Pseudomonas aeruginosa, these fibrils are composed predominantly of FapC, a protein with high-sequence conservation among the genera. Previous studies established FapC as the major amyloid subunit, but its mechanism of fibril formation in P. aeruginosa remained largely unexplored. Here, we examine the FapC sequence in greater detail through a combination of bioinformatics and protein engineering, and we identify specific motifs that are implicated in amyloid formation. Sequence regions of high evolutionary conservation tend to coincide with regions of high amyloid propensity, and mutation of amyloidogenic motifs to a designed, non-amyloidogenic motif suppresses fibril formation in a pH-dependent manner. We establish the particular significance of the third repeat motif in promoting fibril formation and also demonstrate emergence of soluble oligomer species early in the aggregation pathway. The insights reported here expand our understanding of the mechanism of amyloid polymerization in P. aeruginosa, laying the foundation for development of new amyloid inhibitors to combat recalcitrant biofilm infections. (C) 2018 Elsevier Ltd. All rights reserved.

【 授权许可】

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