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-Structure paper
Title | Cryoelectron-microscopy structure of the enteropathogenic type III secretion system EspA filament. |
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Journal, issue, pages | Proc Natl Acad Sci U S A, Vol. 118, Issue 2, Year 2021 |
Publish date | Jan 12, 2021 |
Authors | Weili Zheng / Alejandro Peña / Aravindan Ilangovan / Yasaman Naemi Baghshomali / Gad Frankel / Edward H Egelman / Tiago R D Costa / |
PubMed Abstract | Enteropathogenic (EPEC) and enterohemorrhagic (EHEC) utilize a macromolecular type III secretion system (T3SS) to inject effector proteins into eukaryotic cells. This apparatus spans the inner and ...Enteropathogenic (EPEC) and enterohemorrhagic (EHEC) utilize a macromolecular type III secretion system (T3SS) to inject effector proteins into eukaryotic cells. This apparatus spans the inner and outer bacterial membranes and includes a helical needle protruding into the extracellular space. Thus far observed only in EPEC and EHEC and not found in other pathogenic Gram-negative bacteria that have a T3SS is an additional helical filament made by the EspA protein that forms a long extension to the needle, mediating both attachment to eukaryotic cells and transport of effector proteins through the intestinal mucus layer. Here, we present the structure of the EspA filament from EPEC at 3.4 Å resolution. The structure reveals that the EspA filament is a right-handed 1-start helical assembly with a conserved lumen architecture with respect to the needle to ensure the seamless transport of unfolded cargos en route to the target cell. This functional conservation is despite the fact that there is little apparent overall conservation at the level of sequence or structure with the needle. We also unveil the molecular details of the immunodominant EspA epitope that can now be exploited for the rational design of epitope display systems. |
External links | Proc Natl Acad Sci U S A / PubMed:33397726 / PubMed Central |
Methods | EM (helical sym.) |
Resolution | 3.4 Å |
Structure data | EMDB-22881: Cryo-EM structure of enteropathogenic Escherichia colitype III secretion system EspA filament |
Source |
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Keywords | PROTEIN FIBRIL / type III secretion system (T3SS) / EspA filament / Helical reconstruction |