5J44

Crystal structure of the Secreted Extracellular protein A (SepA) from Shigella flexneri


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.912 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.214 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Shigella depends on SepA to destabilize the intestinal epithelial integrity via cofilin activation.

Maldonado-Contreras, A.Birtley, J.R.Boll, E.Zhao, Y.Mumy, K.L.Toscano, J.Ayehunie, S.Reinecker, H.C.Stern, L.J.McCormick, B.A.

(2017) Gut Microbes 8: 544-560

  • DOI: 10.1080/19490976.2017.1339006

  • PubMed Abstract: 
  • Shigella is unique among enteric pathogens, as it invades colonic epithelia through the basolateral pole. Therefore, it has evolved the ability to breach the intestinal epithelial barrier to deploy an arsenal of effector proteins, which permits bacte ...

    Shigella is unique among enteric pathogens, as it invades colonic epithelia through the basolateral pole. Therefore, it has evolved the ability to breach the intestinal epithelial barrier to deploy an arsenal of effector proteins, which permits bacterial invasion and leads to a severe inflammatory response. However, the mechanisms used by Shigella to regulate epithelial barrier permeability remain unknown. To address this question, we used both an intestinal polarized model and a human ex-vivo model to further characterize the early events of host-bacteria interactions. Our results showed that secreted Serine Protease A (SepA), which belongs to the serine protease autotransporter of Enterobacteriaceae family, is responsible for critically disrupting the intestinal epithelial barrier. Such disruption facilitates bacterial transit to the basolateral pole of the epithelium, ultimately fostering the hallmarks of the disease pathology. SepA was found to cause a decrease in active LIM Kinase 1 (LIMK1) levels, a negative inhibitor of actin-remodeling proteins, namely cofilin. Correspondingly, we observed increased activation of cofilin, a major actin-polymerization factor known to control opening of tight junctions at the epithelial barrier. Furthermore, we resolved the crystal structure of SepA to elucidate its role on actin-dynamics and barrier disruption. The serine protease activity of SepA was found to be required for the regulatory effects on LIMK1 and cofilin, resulting in the disruption of the epithelial barrier during infection. Altogether, we demonstrate that SepA is indispensable for barrier disruption, ultimately facilitating Shigella transit to the basolateral pole where it effectively invades the epithelium.


    Organizational Affiliation

    a Department of Microbiology and Physiological Systems , University of Massachusetts, Medical School , Worcester , MA , USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Serine protease SepA autotransporter
A, B
1033Shigella flexneriMutation(s): 0 
Gene Names: sepA
EC: 3.4.21.-
Find proteins for Q8VSL2 (Shigella flexneri)
Go to UniProtKB:  Q8VSL2
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
EPE
Query on EPE

Download SDF File 
Download CCD File 
A
4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID
HEPES
C8 H18 N2 O4 S
JKMHFZQWWAIEOD-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.912 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.214 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 143.520α = 90.00
b = 143.520β = 90.00
c = 269.250γ = 120.00
Software Package:
Software NamePurpose
SCALAdata scaling
iMOSFLMdata reduction
PHASERphasing
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of Diabetes and Digestive and Kidney DiseaseUnited StatesDK33506

Revision History 

  • Version 1.0: 2017-04-12
    Type: Initial release
  • Version 1.1: 2017-09-27
    Type: Author supporting evidence
  • Version 1.2: 2018-04-11
    Type: Data collection, Database references