Bacterial macroscopic rope-like fibers with cytopathic and adhesive properties.
We present a body of ultrastructural, biochemical, and genetic evidence that demonstrates the oligomerization of virulence-associated autotransporter proteins EspC or EspP produced by deadly human pathogens enterohemorrhagic and enteropathogenic Escherichia coli into novel macroscopic rope-like structures (>1 cm long). The rope-like structures showed high aggregation and insolubility, stability to anionic detergents and high temperature, and binding to Congo Red and thioflavin T dyes. These are properties also exhibited by human amyloidogenic proteins. These macroscopic ropes were not observed in cultures of nonpathogenic Escherichia coli or isogenic espP or espC deletion mutants of enterohemorrhagic or enteropathogenic Escherichia coli but were produced by an Escherichia coli K-12 strain carrying a plasmid expressing espP. Purified recombinant EspP monomers were able to self-assemble into macroscopic ropes upon incubation, suggesting that no other protein was required for assembly. The ropes bound to and showed cytopathic effects on cultured epithelial cells, served as a substratum for bacterial adherence and biofilm formation, and protected bacteria from antimicrobial compounds. We hypothesize that these ropes play a biologically significant role in the survival and pathogenic scheme of these organisms.
Xicohtencatl-Cortes
Juan
J
Laboratorio de Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, Dr. Márquez 162, Col. Doctores, Delegación Cuauhtémoc, México D.F. 06720, México.
Saldaña
Zeus
Z
Deng
Wanyin
W
Castañeda
Elsa
E
Freer
Enrique
E
Tarr
Phil I
PI
Finlay
B Brett
BB
Puente
José Luis
JL
Girón
Jorge A
JA
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001422:Bacterial Adhesion; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D054324:Enterohemorrhagic Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000472:pathogenicity; D054308:Enteropathogenic Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000472:pathogenicity; D004847:Epithelial Cells / Q000378:metabolism / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure
D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; C102541:EspC protein, E coli; C107189:EspP protein, E coli; D012697:Serine Endopeptidases