The formation of Escherichia coli curli amyloid fibrils is mediated by prion-like peptide repeats.
Amyloid fibril formation is the hallmark of major human maladies including Alzheimer's disease, type II diabetes, and prion diseases. Prion-like phenomena were also observed in yeast. Although not evolutionarily related, one similarity between the animal PrP and the yeast Sup35 prion proteins is the occurrence of short peptide repeats that are assumed to play a key role in the assembly of the amyloid structures. It was recently demonstrated that typical amyloid fibril formation is associated with biofilm formation by Escherichia coli. Here, we note the functional and structural similarity between oligopeptide repeats of the major curli protein and those of animal and yeast prions. We demonstrate that synthetic peptides corresponding to the repeats form fibrillar structures. Furthermore, conjugation of beta-breaker elements to the prion-like repeat significantly inhibits amyloid formation and cell invasion of curli-expressing bacteria. This implies a functional role of the repeat in the self-assembly of the fibrils. Since mammal prion, yeast prion, and curli protein are evolutionarily distinct, the conserved peptide repeats most likely define an optimized self-association motif that was independently evolved by diverse systems.
Cherny
Izhack
I
Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
Rockah
Liat
L
Levy-Nissenbaum
Orlev
O
Gophna
Uri
U
Ron
Eliora Z
EZ
Gazit
Ehud
E
D000595:Amino Acid Sequence; D000682:Amyloid / Q000378:metabolism*; D000818:Animals; D003300:Copper / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000235:genetics / Q000378:metabolism*; D010454:Peptide Termination Factors; D011328:Prions / Q000235:genetics; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D000682:Amyloid; D029968:Escherichia coli Proteins; D009842:Oligopeptides; D010454:Peptide Termination Factors; D011328:Prions; C068068:SUP35 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C489688:csgA protein, E coli; D003300:Copper