3PSS

Crystal Structure of AhQnr, the Qnr protein from Aeromonas hydrophila (P21 crystal form)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.233 
  • R-Value Work: 0.179 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structural insights into quinolone antibiotic resistance mediated by pentapeptide repeat proteins: conserved surface loops direct the activity of a Qnr protein from a Gram-negative bacterium

Xiong, X.Bromley, E.H.C.Oelschlaeger, P.Woolfson, D.N.Spencer, J.

(2011) Nucleic Acids Res. --: --

  • DOI: 10.1093/nar/gkq1296
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Quinolones inhibit bacterial type II DNA topoisomerases (e.g. DNA gyrase) and are among the most important antibiotics in current use. However, their efficacy is now being threatened by various plasmid-mediated resistance determinants. Of these, the ...

    Quinolones inhibit bacterial type II DNA topoisomerases (e.g. DNA gyrase) and are among the most important antibiotics in current use. However, their efficacy is now being threatened by various plasmid-mediated resistance determinants. Of these, the pentapeptide repeat-containing (PRP) Qnr proteins are believed to act as DNA mimics and are particularly prevalent in gram-negative bacteria. Predicted Qnr-like proteins are also present in numerous environmental bacteria. Here, we demonstrate that one such, Aeromonas hydrophila AhQnr, is soluble, stable, and relieves quinolone inhibition of Escherichia coli DNA gyrase, thus providing an appropriate model system for gram-negative Qnr proteins. The AhQnr crystal structure, the first for any gram-negative Qnr, reveals two prominent loops (1 and 2) that project from the PRP structure. Deletion mutagenesis demonstrates that both contribute to protection of E. coli DNA gyrase from quinolones. Sequence comparisons indicate that these are likely to be present across the full range of gram-negative Qnr proteins. On this basis we present a model for the AhQnr:DNA gyrase interaction where loop1 interacts with the gyrase A 'tower' and loop2 with the gyrase B TOPRIM domains. We propose this to be a general mechanism directing the interactions of Qnr proteins with DNA gyrase in gram-negative bacteria.


    Organizational Affiliation

    School of Cellular and Molecular Medicine, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Qnr
A, B
216Aeromonas hydrophila subsp. hydrophila (strain ATCC 7966 / DSM 30187 / JCM 1027 / KCTC 2358 / NCIMB 9240)Mutation(s): 0 
Find proteins for A0KF03 (Aeromonas hydrophila subsp. hydrophila (strain ATCC 7966 / DSM 30187 / JCM 1027 / KCTC 2358 / NCIMB 9240))
Go to UniProtKB:  A0KF03
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MLY
Query on MLY
A, B
L-PEPTIDE LINKINGC8 H18 N2 O2LYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.233 
  • R-Value Work: 0.179 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 52.230α = 90.00
b = 57.710β = 106.96
c = 85.120γ = 90.00
Software Package:
Software NamePurpose
ADSCdata collection
REFMACrefinement
MOSFLMdata reduction
SOLVEphasing
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2010-12-02 
  • Released Date: 2011-01-26 
  • Deposition Author(s): Xiong, X., Spencer, J.

Revision History 

  • Version 1.0: 2011-01-26
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance