6PDK

The Structure of Smlt3025, an immunity protein of the Stenotrophomonas maltophilia type IV secretion system


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.200 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

The opportunistic pathogen Stenotrophomonas maltophilia utilizes a type IV secretion system for interbacterial killing.

Bayer-Santos, E.Cenens, W.Matsuyama, B.Y.Oka, G.U.Di Sessa, G.Mininel, I.D.V.Alves, T.L.Farah, C.S.

(2019) PLoS Pathog 15: e1007651-e1007651

  • DOI: 10.1371/journal.ppat.1007651
  • Primary Citation of Related Structures:  
    6PDK

  • PubMed Abstract: 
  • Bacterial type IV secretion systems (T4SS) are a highly diversified but evolutionarily related family of macromolecule transporters that can secrete proteins and DNA into the extracellular medium or into target cells. It was recently shown that a subtype of T4SS harboured by the plant pathogen Xanthomonas citri transfers toxins into target cells ...

    Bacterial type IV secretion systems (T4SS) are a highly diversified but evolutionarily related family of macromolecule transporters that can secrete proteins and DNA into the extracellular medium or into target cells. It was recently shown that a subtype of T4SS harboured by the plant pathogen Xanthomonas citri transfers toxins into target cells. Here, we show that a similar T4SS from the multi-drug-resistant opportunistic pathogen Stenotrophomonas maltophilia is proficient in killing competitor bacterial species. T4SS-dependent duelling between S. maltophilia and X. citri was observed by time-lapse fluorescence microscopy. A bioinformatic search of the S. maltophilia K279a genome for proteins containing a C-terminal domain conserved in X. citri T4SS effectors (XVIPCD) identified twelve putative effectors and their cognate immunity proteins. We selected a putative S. maltophilia effector with unknown function (Smlt3024) for further characterization and confirmed that it is indeed secreted in a T4SS-dependent manner. Expression of Smlt3024 in the periplasm of E. coli or its contact-dependent delivery via T4SS into E. coli by X. citri resulted in reduced growth rates, which could be counteracted by expression of its cognate inhibitor Smlt3025 in the target cell. Furthermore, expression of the VirD4 coupling protein of X. citri can restore the function of S. maltophilia ΔvirD4, demonstrating that effectors from one species can be recognized for transfer by T4SSs from another species. Interestingly, Smlt3024 is homologous to the N-terminal domain of large Ca2+-binding RTX proteins and the crystal structure of Smlt3025 revealed a topology similar to the iron-regulated protein FrpD from Neisseria meningitidis which has been shown to interact with the RTX protein FrpC. This work expands our current knowledge about the function of bacteria-killing T4SSs and increases the panel of effectors known to be involved in T4SS-mediated interbacterial competition, which possibly contribute to the establishment of S. maltophilia in clinical and environmental settings.


    Organizational Affiliation

    Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Uncharacterized proteinA269Stenotrophomonas maltophilia K279aMutation(s): 0 
Gene Names: Smlt3025
UniProt
Find proteins for B2FJJ6 (Stenotrophomonas maltophilia (strain K279a))
Explore B2FJJ6 
Go to UniProtKB:  B2FJJ6
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
BR
Query on BR

Download Ideal Coordinates CCD File 
F [auth A] , G [auth A] , H [auth A] , I [auth A] , J [auth A] , K [auth A] , L [auth A] , M [auth A] , 
F [auth A],  G [auth A],  H [auth A],  I [auth A],  J [auth A],  K [auth A],  L [auth A],  M [auth A],  N [auth A],  O [auth A],  P [auth A]
BROMIDE ION
Br
CPELXLSAUQHCOX-UHFFFAOYSA-M
 Ligand Interaction
CL
Query on CL

Download Ideal Coordinates CCD File 
B [auth A], C [auth A], D [auth A], E [auth A]CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.200 
  • Space Group: H 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.532α = 90
b = 67.532β = 90
c = 149.386γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XDSdata scaling
PHENIXphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Fundacao para a Ciencia e a TecnologiaBrazil2017/17303-7
Fundacao para a Ciencia e a TecnologiaBrazil2016/00458-5

Revision History  (Full details and data files)

  • Version 1.0: 2019-09-04
    Type: Initial release
  • Version 1.1: 2019-09-25
    Changes: Data collection, Database references