Conversion of the OmpF Porin into a Device to Gather Amyloids on the E. coli Outer Membrane

Abstract

Protein amyloids are ubiquitous in natural environments. They typically originate from microbial secretions or spillages from mammals infected by prions, currently raising concerns about their infectivity and toxicity in contexts such as gut microbiota or soils. Exploiting the self-assembly potential of amyloids for their scavenging, here, we report the insertion of an amyloidogenic sequence stretch from a bacterial prion-like protein (RepA-WH1) in one of the extracellular loops (L5) of the abundant Escherichia coli outer membrane porin OmpF. The expression of this grafted porin enables bacterial cells to trap on their envelopes the same amyloidogenic sequence when provided as an extracellular free peptide. Conversely, when immobilized on a surface as bait, the full-length prion-like protein including the amyloidogenic peptide can catch bacteria displaying the L5-grafted OmpF. Polyphenolic molecules known to inhibit amyloid assembly interfere with peptide recognition by the engineered OmpF, indicating that this is compatible with the kind of homotypic interactions expected for amyloid assembly. Our study suggests that synthetic porins may provide suitable scaffolds for engineering biosensor and clearance devices to tackle the threat posed by pathogenic amyloids.

Molecular characterization of the N-terminal half of TasA during amyloid-like assembly and its contribution to Bacillus subtilis biofilm formation

“…Unfortunately, we were unable to characterize the TasA variants lacking these amyloidogenic regions, as their deletion resulted in the degradation of the protein. These regions are known to be of utmost importance to explain the molecular behavior of amyloid proteins 38 , 39 , and given the ability of amyloids to self-assemble through protein‒protein interactions, these stretches serve novel approaches in synthetic biology and biotechnology, for example, to capture free amyloid peptides or proteins or even bacteria themselves when exhibiting these sequences on their surface 40 . The fact that these mutated proteins are eliminated to undetectable levels and the different phenotypes of strains expressing their alleles compared to the Δ tasA strain or any other ECM-defective strain suggest a relevant contribution to the native folding features of TasA.…”

Molecular characterization of the N-terminal half of TasA during functional amyloid assembly and its contribution toBacillus subtilisbiofilm formation

“…Unfortunately, we were unable to characterize the TasA variants lacking these amyloidogenic regions, as their deletion resulted in the degradation of the protein. These regions are known to be of utmost importance to explain the molecular behavior of amyloid proteins 36, 37 , and given the ability of amyloids to self-assemble through protein‒protein interactions, these stretches serve novel approaches in synthetic biology and biotechnology, for example, to capture free amyloid peptides or proteins or even bacteria themselves when exhibiting these sequences on their surface 38 . The fact that these mutated proteins are eliminated to undetectable levels and the different phenotypes of strains expressing their alleles compared to the Δ tasA strain or any other ECM-defective strain suggest a relevant contribution to the native folding features of TasA.…”

Bacterial biofilm functionalization through Bap amyloid engineering

“…In the same way, the amyloid protein TasA has also been engineered for conferring living glues properties to B. subtilis biofilms 35 and printing of this functionalized biofilm was performed in 3D 9 . Moreover, other groups have focused on the use of amyloids in bioremediation 16 , biosensing 37 or clearance of pathological amyloids found in nature 38 , among other applications.…”