SeMet-Rns, in complex with potential inhibitor

Experimental Data Snapshot

  • Resolution: 2.80 Å
  • R-Value Free: 0.300 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.248 

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Structure of the master regulator Rns reveals an inhibitor of enterotoxigenic Escherichia coli virulence regulons.

Midgett, C.R.Talbot, K.M.Day, J.L.Munson, G.P.Kull, F.J.

(2021) Sci Rep 11: 15663-15663

  • DOI: https://doi.org/10.1038/s41598-021-95123-2
  • Primary Citation of Related Structures:  
    6XIU, 6XIV

  • PubMed Abstract: 

    Enteric infections caused by the gram-negative bacteria enterotoxigenic Escherichia coli (ETEC), Vibrio cholerae, Shigella flexneri, and Salmonella enterica are among the most common and affect billions of people each year. These bacteria control expression of virulence factors using a network of transcriptional regulators, some of which are modulated by small molecules as has been shown for ToxT, an AraC family member from V. cholerae. In ETEC the expression of many types of adhesive pili is dependent upon the AraC family member Rns. We present here the 3 Å crystal structure of Rns and show it closely resembles ToxT. Rns crystallized as a dimer via an interface similar to that observed in other dimeric AraC's. Furthermore, the structure of Rns revealed the presence of a ligand, decanoic acid, that inhibits its activity in a manner similar to the fatty acid mediated inhibition observed for ToxT and the S. enterica homologue HilD. Together, these results support our hypothesis that fatty acids regulate virulence controlling AraC family members in a common manner across a number of enteric pathogens. Furthermore, for the first time this work identifies a small molecule capable of inhibiting the ETEC Rns regulon, providing a basis for development of therapeutics against this deadly human pathogen.

  • Organizational Affiliation

    Department of Chemistry, Dartmouth College, Hanover, NH, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Regulatory protein Rns
A, B
265Escherichia coliMutation(s): 0 
Gene Names: rns
Find proteins for P16114 (Escherichia coli)
Explore P16114 
Go to UniProtKB:  P16114
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP16114
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
A, B
Experimental Data & Validation

Experimental Data

  • Resolution: 2.80 Å
  • R-Value Free: 0.300 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.248 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 72.51α = 90
b = 49.97β = 106.11
c = 102.92γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United StatesR21AI060031

Revision History  (Full details and data files)

  • Version 1.0: 2021-06-30
    Type: Initial release
  • Version 1.1: 2022-02-02
    Changes: Database references