2XTY

Structure of QnrB1 (R167E-Trypsin Treated), a plasmid-mediated fluoroquinolone resistance protein


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.221 
  • R-Value Work: 0.180 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of Qnrb1, a Plasmid-Mediated Fluoroquinolone Resistance Factor.

Vetting, M.W.Hegde, S.S.Wang, M.Jacoby, G.A.Hooper, D.C.Blanchard, J.S.

(2011) J.Biol.Chem. 286: 25265

  • DOI: 10.1074/jbc.M111.226936
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • QnrB1 is a plasmid-encoded pentapeptide repeat protein (PRP) that confers a moderate degree of resistance to fluoroquinolones. Its gene was cloned into an expression vector with an N-terminal polyhistidine tag, and the protein was purified by nickel ...

    QnrB1 is a plasmid-encoded pentapeptide repeat protein (PRP) that confers a moderate degree of resistance to fluoroquinolones. Its gene was cloned into an expression vector with an N-terminal polyhistidine tag, and the protein was purified by nickel affinity chromatography. The structure of QnrB1 was determined by a combination of trypsinolysis, surface mutagenesis, and single anomalous dispersion phasing. QnrB1 folds as a right-handed quadrilateral β-helix with a highly asymmetric dimeric structure typical of PRP-topoisomerase poison resistance factors. The threading of pentapeptides into the β-helical fold is interrupted by two noncanonical PRP sequences that produce outward projecting loops that interrupt the regularity of the PRP surface. Deletion of the larger upper loop eliminated the protective effect of QnrB1 on DNA gyrase toward inhibition by quinolones, whereas deletion of the smaller lower loop drastically reduced the protective effect. These loops are conserved among all plasmid-based Qnr variants (QnrA, QnrC, QnrD, and QnrS) and some chromosomally encoded Qnr varieties. A mechanism in which PRP-topoisomerase poison resistance factors bind to and disrupt the quinolone-DNA-gyrase interaction is proposed.


    Organizational Affiliation

    Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
QNRB1
A, B
217Klebsiella pneumoniaeMutation(s): 1 
Gene Names: qnrB1 (pipB2)
Find proteins for Q2I1Y8 (Klebsiella pneumoniae)
Go to UniProtKB:  Q2I1Y8
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.221 
  • R-Value Work: 0.180 
  • Space Group: P 41 21 2
Unit Cell:
Length (Å)Angle (°)
a = 55.330α = 90.00
b = 55.330β = 90.00
c = 282.460γ = 90.00
Software Package:
Software NamePurpose
PHENIXphasing
PHENIXrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-10-27
    Type: Initial release
  • Version 1.1: 2011-07-27
    Type: Database references, Version format compliance
  • Version 1.2: 2019-05-08
    Type: Data collection, Experimental preparation, Other