5U8M

A novel family of redox sensors in the streptococci evolved from two-component response regulators


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.191 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

RitR is an archetype for a novel family of redox sensors in the streptococci that has evolved from two-component response regulators and is required for pneumococcal colonization.

Glanville, D.G.Han, L.Maule, A.F.Woodacre, A.Thanki, D.Abdullah, I.T.Morrissey, J.A.Clarke, T.B.Yesilkaya, H.Silvaggi, N.R.Ulijasz, A.T.

(2018) PLoS Pathog 14: e1007052-e1007052

  • DOI: https://doi.org/10.1371/journal.ppat.1007052
  • Primary Citation of Related Structures:  
    5U8K, 5U8M, 5VFA

  • PubMed Abstract: 

    To survive diverse host environments, the human pathogen Streptococcus pneumoniae must prevent its self-produced, extremely high levels of peroxide from reacting with intracellular iron. However, the regulatory mechanism(s) by which the pneumococcus accomplishes this balance remains largely enigmatic, as this pathogen and other related streptococci lack all known redox-sensing transcription factors. Here we describe a two-component-derived response regulator, RitR, as the archetype for a novel family of redox sensors in a subset of streptococcal species. We show that RitR works to both repress iron transport and enable nasopharyngeal colonization through a mechanism that exploits a single cysteine (Cys128) redox switch located within its linker domain. Biochemical experiments and phylogenetics reveal that RitR has diverged from the canonical two-component virulence regulator CovR to instead dimerize and bind DNA only upon Cys128 oxidation in air-rich environments. Atomic structures show that Cys128 oxidation initiates a "helical unravelling" of the RitR linker region, suggesting a mechanism by which the DNA-binding domain is then released to interact with its cognate regulatory DNA. Expanded computational studies indicate this mechanism could be shared by many microbial species outside the streptococcus genus.


  • Organizational Affiliation

    Department of Microbiology and Immunology, Loyola University Chicago; Maywood, IL, United States of America.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Response regulator
A, B
231Streptococcus pneumoniae Hungary19A-6Mutation(s): 0 
Gene Names: SPH_0483
UniProt
Find proteins for B1I9H6 (Streptococcus pneumoniae (strain Hungary19A-6))
Explore B1I9H6 
Go to UniProtKB:  B1I9H6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupB1I9H6
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.191 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 74.33α = 90
b = 74.832β = 90
c = 102.799γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2017-12-20
    Type: Initial release
  • Version 1.1: 2018-11-28
    Changes: Data collection, Database references
  • Version 1.2: 2023-10-04
    Changes: Data collection, Database references, Refinement description