7AGX

Apo-state type 3 secretion system export apparatus complex from Salmonella enterica typhimurium


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.60 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Substrate-engaged type III secretion system structures reveal gating mechanism for unfolded protein translocation.

Miletic, S.Fahrenkamp, D.Goessweiner-Mohr, N.Wald, J.Pantel, M.Vesper, O.Kotov, V.Marlovits, T.C.

(2021) Nat Commun 12: 1546-1546

  • DOI: https://doi.org/10.1038/s41467-021-21143-1
  • Primary Citation of Related Structures:  
    7AGX

  • PubMed Abstract: 

    Many bacterial pathogens rely on virulent type III secretion systems (T3SSs) or injectisomes to translocate effector proteins in order to establish infection. The central component of the injectisome is the needle complex which assembles a continuous conduit crossing the bacterial envelope and the host cell membrane to mediate effector protein translocation. However, the molecular principles underlying type III secretion remain elusive. Here, we report a structure of an active Salmonella enterica serovar Typhimurium needle complex engaged with the effector protein SptP in two functional states, revealing the complete 800Å-long secretion conduit and unraveling the critical role of the export apparatus (EA) subcomplex in type III secretion. Unfolded substrates enter the EA through a hydrophilic constriction formed by SpaQ proteins, which enables side chain-independent substrate transport. Above, a methionine gasket formed by SpaP proteins functions as a gate that dilates to accommodate substrates while preventing leaky pore formation. Following gate penetration, a moveable SpaR loop first folds up to then support substrate transport. Together, these findings establish the molecular basis for substrate translocation through T3SSs and improve our understanding of bacterial pathogenicity and motility.


  • Organizational Affiliation

    University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Surface presentation of antigens protein SpaPA [auth 1A],
B [auth 1B],
C [auth 1C],
D [auth 1D],
E [auth 1E]
224Salmonella enterica subsp. enterica serovar Typhimurium str. LT2Mutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for P40700 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
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Go to UniProtKB:  P40700
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UniProt GroupP40700
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Surface presentation of antigens protein SpaRF [auth 1F]263Salmonella enterica subsp. enterica serovar Typhimurium str. LT2Mutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for P40701 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
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UniProt GroupP40701
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Surface presentation of antigens protein SpaQG [auth 1G],
H [auth 1H],
I [auth 1I],
J [auth 1J]
86Salmonella enterica subsp. enterica serovar Typhimurium str. LT2Mutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for P0A1L7 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
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UniProt GroupP0A1L7
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Entity ID: 4
MoleculeChains Sequence LengthOrganismDetailsImage
Protein PrgJ101Salmonella enterica subsp. enterica serovar Typhimurium str. LT2Mutation(s): 0 
UniProt
Find proteins for P41785 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
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UniProt GroupP41785
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Entity ID: 5
MoleculeChains Sequence LengthOrganismDetailsImage
Protein PrgI80Salmonella enterica subsp. enterica serovar Typhimurium str. LT2Mutation(s): 0 
UniProt
Find proteins for P41784 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Explore P41784 
Go to UniProtKB:  P41784
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UniProt GroupP41784
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.60 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion
MODEL REFINEMENTISOLDE1.0b5
MODEL REFINEMENTPHENIX1.18-6831

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Austrian Science FundAustriaI 2408-B22
German Research Foundation (DFG)GermanyFA1518/2-1

Revision History  (Full details and data files)

  • Version 1.0: 2021-03-17
    Type: Initial release
  • Version 1.1: 2021-03-31
    Changes: Database references
  • Version 1.2: 2024-05-01
    Changes: Data collection, Database references