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Title | Cryo-EM structure of the EspA filament from enteropathogenic Escherichia coli: Revealing the mechanism of effector translocation in the T3SS. |
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Journal, issue, pages | Structure, Vol. 29, Issue 5, Page 479-487.e4, Year 2021 |
Publish date | May 6, 2021 |
![]() | Bronwyn J E Lyons / Claire E Atkinson / Wanyin Deng / Antonio Serapio-Palacios / B Brett Finlay / Natalie C J Strynadka / ![]() |
PubMed Abstract | The type III secretion system (T3SS) is a virulence mechanism employed by Gram-negative pathogens. The T3SS forms a proteinaceous channel that projects a needle into the extracellular medium where it ...The type III secretion system (T3SS) is a virulence mechanism employed by Gram-negative pathogens. The T3SS forms a proteinaceous channel that projects a needle into the extracellular medium where it interacts with the host cell to deliver virulence factors. Enteropathogenic Escherichia coli (EPEC) is unique in adopting a needle extension to the T3SS-a filament formed by EspA-which is absolutely required for efficient colonization of the gut. Here, we describe the cryoelectron microscopy structure of native EspA filaments from EPEC at 3.6-Å resolution. Within the filament, positively charged residues adjacent to a hydrophobic groove line the lumen of the filament in a spiral manner, suggesting a mechanism of substrate translocation mediated via electrostatics. Using structure-guided mutagenesis, in vivo studies corroborate the role of these residues in secretion and translocation function. The high-resolution structure of the EspA filament could aid in structure-guided drug design of antivirulence therapeutics. |
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Methods | EM (helical sym.) |
Resolution | 3.56 Å |
Structure data | EMDB-22701, PDB-7k7k: |
Source |
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![]() | PROTEIN TRANSPORT / Transport / filament / secretion system |