2ACO

Xray structure of Blc dimer in complex with vaccenic acid


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.171 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The membrane bound bacterial lipocalin Blc is a functional dimer with binding preference for lysophospholipids.

Campanacci, V.Bishop, R.E.Blangy, S.Tegoni, M.Cambillau, C.

(2006) Febs Lett. 580: 4877-4883

  • DOI: 10.1016/j.febslet.2006.07.086

  • PubMed Abstract: 
  • Lipocalins, a widespread multifunctional family of small proteins (15-25kDa) have been first described in eukaryotes and more recently in Gram-negative bacteria. Bacterial lipocalins belonging to class I are outer membrane lipoproteins, among which B ...

    Lipocalins, a widespread multifunctional family of small proteins (15-25kDa) have been first described in eukaryotes and more recently in Gram-negative bacteria. Bacterial lipocalins belonging to class I are outer membrane lipoproteins, among which Blc from E. coli is the better studied. Blc is expressed under conditions of starvation and high osmolarity, conditions known to exert stress on the cell envelope. The structure of Blc that we have previously solved (V. Campanacci, D. Nurizzo, S. Spinelli, C. Valencia, M. Tegoni, C. Cambillau, FEBS Lett. 562 (2004) 183-188.) suggested its possible role in binding fatty acids or phospholipids. Both physiological and structural data on Blc, therefore, point to a role in storage or transport of lipids necessary for membrane maintenance. In order to further document this hypothesis for Blc function, we have performed binding studies using fluorescence quenching experiments. Our results indicate that dimeric Blc binds fatty acids and phospholipids in a micromolar K(d) range. The crystal structure of Blc with vaccenic acid, an unsaturated C18 fatty acid, reveals that the binding site spans across the Blc dimer, opposite to its membrane anchored face. An exposed unfilled pocket seemingly suited to bind a polar group attached to the fatty acid prompted us to investigate lyso-phospholipids, which were found to bind in a nanomolar K(d) range. We discuss these findings in terms of a potential role for Blc in the metabolism of lysophospholipids generated in the bacterial outer membrane.


    Organizational Affiliation

    Architecture et Fonction des Macromolecules Biologiques, UMR 6098, CNRS-Universit├ęs Aix-Marseille I & II, Campus de Luminy, Case 932, 163 Avenue de Luminy, 13288 Marseille Cedex 09, France.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Outer membrane lipoprotein blc
A, B
173Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: blc (yjeL)
Find proteins for P0A901 (Escherichia coli (strain K12))
Go to UniProtKB:  P0A901
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
VCA
Query on VCA

Download SDF File 
Download CCD File 
B
VACCENIC ACID
(11E)-OCTADEC-11-ENOIC ACID
C18 H34 O2
UWHZIFQPPBDJPM-FPLPWBNLSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
VCAKd: 2500 nM BINDINGMOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.171 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 57.901α = 90.00
b = 81.337β = 90.00
c = 89.020γ = 90.00
Software Package:
Software NamePurpose
CCP4data scaling
MOSFLMdata reduction
REFMACrefinement
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-08-01
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance