Crystal structure of Pseudomonas aeruginosa OprO

Experimental Data Snapshot

  • Resolution: 1.52 Å
  • R-Value Free: 0.168 
  • R-Value Work: 0.150 
  • R-Value Observed: 0.151 

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Structure, Dynamics, and Substrate Specificity of the OprO Porin from Pseudomonas aeruginosa.

Modi, N.Ganguly, S.Barcena-Uribarri, I.Benz, R.van den Berg, B.Kleinekathofer, U.

(2015) Biophys J 109: 1429-1438

  • DOI: https://doi.org/10.1016/j.bpj.2015.07.035
  • Primary Citation of Related Structures:  
    4RJW, 4RJX

  • PubMed Abstract: 

    The outer membrane (OM) of Gram-negative bacteria functions as a selective permeability barrier between cell and environment. For nutrient acquisition, the OM contains a number of channels that mediate uptake of small molecules by diffusion. Many of these channels are specific, i.e., they prefer certain substrates over others. In electrophysiological experiments, the OM channels OprP and OprO from Pseudomonas aeruginosa show a specificity for phosphate and diphosphate, respectively. In this study we use x-ray crystallography, free-energy molecular dynamics (MD) simulations, and electrophysiology to uncover the atomic basis for the different substrate specificity of these highly similar channels. A structural analysis of OprP and OprO revealed two crucial differences in the central constriction region. In OprP there are two tyrosine residues, Y62 and Y114, whereas the corresponding residues in OprO are phenylalanine F62 and aspartate D114. To probe the importance of these two residues in generating the different substrate specificities, the double mutants were generated in silico and in vitro. Applied-field MD simulations and electrophysiological experiments demonstrated that the double mutations interchange the phosphate and diphosphate specificities of OprP and OprO. Our findings outline a possible strategy to rationally design channel specificity by modification of a small number of residues that may be applicable to other pores as well.

  • Organizational Affiliation

    Department of Physics and Earth Sciences, Jacobs University Bremen, Bremen, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Porin O429Pseudomonas aeruginosa PAO1Mutation(s): 0 
Gene Names: oprOPA3280
Membrane Entity: Yes 
Find proteins for P32977 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Explore P32977 
Go to UniProtKB:  P32977
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP32977
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.52 Å
  • R-Value Free: 0.168 
  • R-Value Work: 0.150 
  • R-Value Observed: 0.151 
  • Space Group: H 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 86.971α = 90
b = 86.971β = 90
c = 158.5γ = 120
Software Package:
Software NamePurpose
CBASSdata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-10-21
    Type: Initial release
  • Version 1.1: 2024-02-28
    Changes: Data collection, Database references, Derived calculations