2XG6

Molecular insights into clinically isolated OmpC mutants and their role in multi-drug resistance


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.47 Å
  • R-Value Free: 0.293 
  • R-Value Work: 0.261 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Altered Antibiotic Transport in Ompc Mutants Isolated from a Series of Clinical Strains of Multi-Drug Resistant E. Coli.

Lou, H.Chen, M.Black, S.S.Bushell, S.R.Ceccarelli, M.Mach, T.Beis, K.Low, A.S.Bamford, V.A.Booth, I.R.Bayley, H.Naismith, J.H.

(2011) Plos One 6: 25825

  • DOI: 10.1371/journal.pone.0025825
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Antibiotic-resistant bacteria, particularly gram negative species, present significant health care challenges. The permeation of antibiotics through the outer membrane is largely effected by the porin superfamily, changes in which contribute to antib ...

    Antibiotic-resistant bacteria, particularly gram negative species, present significant health care challenges. The permeation of antibiotics through the outer membrane is largely effected by the porin superfamily, changes in which contribute to antibiotic resistance. A series of antibiotic resistant E. coli isolates were obtained from a patient during serial treatment with various antibiotics. The sequence of OmpC changed at three positions during treatment giving rise to a total of four OmpC variants (denoted OmpC20, OmpC26, OmpC28 and OmpC33, in which OmpC20 was derived from the first clinical isolate). We demonstrate that expression of the OmpC K12 porin in the clinical isolates lowers the MIC, consistent with modified porin function contributing to drug resistance. By a range of assays we have established that the three mutations that occur between OmpC20 and OmpC33 modify transport of both small molecules and antibiotics across the outer membrane. This results in the modulation of resistance to antibiotics, particularly cefotaxime. Small ion unitary conductance measurements of the isolated porins do not show significant differences between isolates. Thus, resistance does not appear to arise from major changes in pore size. Crystal structures of all four OmpC clinical mutants and molecular dynamics simulations also show that the pore size is essentially unchanged. Molecular dynamics simulations suggest that perturbation of the transverse electrostatic field at the constriction zone reduces cefotaxime passage through the pore, consistent with laboratory and clinical data. This subtle modification of the transverse electric field is a very different source of resistance than occlusion of the pore or wholesale destruction of the transverse field and points to a new mechanism by which porins may modulate antibiotic passage through the outer membrane.


    Organizational Affiliation

    Centre for Biomolecular Sciences, University of St Andrews, St Andrews, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
OMPC
A, B, C, D, E, F
343Escherichia coliMutation(s): 0 
Gene Names: ompC
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: BETA-BARREL
Sub Group: 
Beta-Barrel Membrane Proteins: Porins and Relatives
Protein: 
OmpC Osmoporin
Find proteins for Q9K597 (Escherichia coli)
Go to UniProtKB:  Q9K597
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, C, D
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.47 Å
  • R-Value Free: 0.293 
  • R-Value Work: 0.261 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 142.820α = 90.00
b = 159.725β = 90.00
c = 164.601γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
REFMACrefinement
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-07-14
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Version format compliance
  • Version 1.2: 2011-11-16
    Type: Database references