7K7K

Structure of the EPEC type III secretion injectisome EspA filament

Summary for 7K7K

• Entry DOI: 10.2210/pdb7k7k/pdb
• EMDB information: 22701
• Descriptor: Translocon EspA (1 entity in total)
• Functional Keywords: transport, filament, secretion system, protein transport
• Biological source: Escherichia coli O127:H6 (strain E2348/69 / EPEC)
• Total number of polymer chains: 28
• Total formula weight: 573518.71

Authors

Lyons, B.J.E.,Atkinson, C.E.,Strynadka, N.C.J. (deposition date: 2020-09-23, release date: 2020-12-30, Last modification date: 2024-03-06)

Primary citation

Lyons, B.J.E.,Atkinson, C.E.,Deng, W.,Serapio-Palacios, A.,Finlay, B.B.,Strynadka, N.C.J.
Cryo-EM structure of the EspA filament from enteropathogenic Escherichia coli: Revealing the mechanism of effector translocation in the T3SS.
Structure, 29:479-, 2021

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 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.

PubMed: 33453150
DOI: 10.1016/j.str.2020.12.009

Experimental method

ELECTRON MICROSCOPY (3.56 Å)