1BT9

OMPF PORIN MUTANT D74A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.191 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Stability of trimeric OmpF porin: the contributions of the latching loop L2.

Phale, P.S.Philippsen, A.Kiefhaber, T.Koebnik, R.Phale, V.P.Schirmer, T.Rosenbusch, J.P.

(1998) Biochemistry 37: 15663-15670

  • DOI: 10.1021/bi981215c

  • PubMed Abstract: 
  • The channel-forming protein OmpF porin from Escherichia coli spans the bacterial outer membrane. Each of the three monomers comprises a hollow, 16-stranded beta-barrel. These are associated to homotrimers which are unusually stable, due mostly to hyd ...

    The channel-forming protein OmpF porin from Escherichia coli spans the bacterial outer membrane. Each of the three monomers comprises a hollow, 16-stranded beta-barrel. These are associated to homotrimers which are unusually stable, due mostly to hydrophobic interactions between the beta-barrels. In addition, a loop, L2 connects one subunit to its neighbor by latching into its channel. Residue E71 on loop 2 is integrated into an ionic network and forms salt bridges and hydrogen bonds with R100 and R132 on the channel wall in the adjacent subunit. To examine these contributions quantitatively, six single-site, two double, and one deletion mutant were constructed on the basis of the atomic coordinates of the protein. Differential scanning calorimetric analysis showed that the salt-bridge, E71-R100, contributes significantly to trimer stability: the substitution E71Q causes a decrease of the transition temperature from 72 to 48 degreesC, with DeltaHcal diminishing from 430 to 201 kcal mol-1. A nearby substitution in the loop, D74N, has lesser effects on thermal stability, while the deletion in L2 (Delta69-77) has an effect comparable to that of E71Q. X-ray structure analysis to 3.0 A resolution revealed only local structural differences in the mutants except for the substitution R100A, where another residue, R132, is found to fill the gap left by the truncated side chain of A100. Functional assays in planar lipid bilayers show significantly increased cation selectivities if the charge distribution was affected.


    Related Citations: 
    • Crystal Structures Explain Functional Properties of Two E.Coli Porins
      Cowan, S.W.,Schirmer, T.,Rummel, G.,Steiert, M.,Ghosh, R.,Pauptit, R.A.,Jansonius, J.N.,Rosenbusch, J.P.
      (1992) Nature 358: 727


    Organizational Affiliation

    Division of Microbiology, Biozentrum, University of Basel, Switzerland.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PROTEIN (MATRIX PORIN OUTER MEMBRANE PROTEIN F)
A
340Escherichia coli (strain K12)Mutation(s): 1 
Gene Names: ompF (cmlB, coa, cry, tolF)
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: BETA-BARREL
Sub Group: 
Beta-Barrel Membrane Proteins: Porins and Relatives
Protein: 
OmpF Porin
Find proteins for P02931 (Escherichia coli (strain K12))
Go to UniProtKB:  P02931
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.191 
  • Space Group: P 3 2 1
Unit Cell:
Length (Å)Angle (°)
a = 118.500α = 90.00
b = 118.500β = 90.00
c = 52.700γ = 120.00
Software Package:
Software NamePurpose
SFALLphasing
SFALLmodel building
REFMACrefinement
MOSFLMdata reduction
CCP4data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-01-13
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Source and taxonomy, Version format compliance
  • Version 1.3: 2017-10-04
    Type: Advisory