6WEG

Structure of Ft (MglA-SspA)-ppGpp-PigR peptide complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.95 Å
  • R-Value Free: 0.290 
  • R-Value Work: 0.225 
  • R-Value Observed: 0.230 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural Basis for Virulence Activation of Francisella tularensis.

Travis, B.A.Ramsey, K.M.Prezioso, S.M.Tallo, T.Wandzilak, J.M.Hsu, A.Borgnia, M.Bartesaghi, A.Dove, S.L.Brennan, R.G.Schumacher, M.A.

(2021) Mol Cell 81: 139-152.e10

  • DOI: https://doi.org/10.1016/j.molcel.2020.10.035
  • Primary Citation of Related Structures:  
    6WEG, 6WMP, 6WMR, 6WMT, 6WMU

  • PubMed Abstract: 

    The bacterium Francisella tularensis (Ft) is one of the most infectious agents known. Ft virulence is controlled by a unique combination of transcription regulators: the MglA-SspA heterodimer, PigR, and the stress signal, ppGpp. MglA-SspA assembles with the σ 70 -associated RNAP holoenzyme (RNAPσ 70 ), forming a virulence-specialized polymerase. These factors activate Francisella pathogenicity island (FPI) gene expression, which is required for virulence, but the mechanism is unknown. Here we report FtRNAPσ 70 -promoter-DNA, FtRNAPσ 70 -(MglA-SspA)-promoter DNA, and FtRNAPσ 70 -(MglA-SspA)-ppGpp-PigR-promoter DNA cryo-EM structures. Structural and genetic analyses show MglA-SspA facilitates σ 70 binding to DNA to regulate virulence and virulence-enhancing genes. Our Escherichia coli RNAPσ 70- homodimeric EcSspA structure suggests this is a general SspA-transcription regulation mechanism. Strikingly, our FtRNAPσ 70 -(MglA-SspA)-ppGpp-PigR-DNA structure reveals ppGpp binding to MglA-SspA tethers PigR to promoters. PigR in turn recruits FtRNAP αCTDs to DNA UP elements. Thus, these studies unveil a unique mechanism for Ft pathogenesis involving a virulence-specialized RNAP that employs two (MglA-SspA)-based strategies to activate virulence genes.


  • Organizational Affiliation

    Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Stringent starvation protein A, regulator of transcriptionA [auth C],
C [auth D]
211Francisella tularensis subsp. tularensis SCHU S4Mutation(s): 0 
Gene Names: sspAFTT_0458
UniProt
Find proteins for Q5NHJ6 (Francisella tularensis subsp. tularensis (strain SCHU S4 / Schu 4))
Explore Q5NHJ6 
Go to UniProtKB:  Q5NHJ6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ5NHJ6
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
MglAB [auth A],
D [auth B]
204Francisella tularensisMutation(s): 0 
Gene Names: DR86_1530
UniProt
Find proteins for Q5NFG1 (Francisella tularensis subsp. tularensis (strain SCHU S4 / Schu 4))
Explore Q5NFG1 
Go to UniProtKB:  Q5NFG1
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UniProt GroupQ5NFG1
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  • Reference Sequence

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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
PeptideE [auth P]22Francisella tularensis subsp. tularensis SCHU S4Mutation(s): 0 
Gene Names: FTT_0383
UniProt
Find proteins for Q5NHR4 (Francisella tularensis subsp. tularensis (strain SCHU S4 / Schu 4))
Explore Q5NHR4 
Go to UniProtKB:  Q5NHR4
Entity Groups  
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UniProt GroupQ5NHR4
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.95 Å
  • R-Value Free: 0.290 
  • R-Value Work: 0.225 
  • R-Value Observed: 0.230 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 65.756α = 90
b = 113.562β = 90
c = 141.073γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
SCALAdata scaling
MOLREPphasing
PDB_EXTRACTdata extraction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2020-11-11
    Type: Initial release
  • Version 1.1: 2021-05-26
    Changes: Database references
  • Version 1.2: 2023-10-18
    Changes: Data collection, Database references, Refinement description