2ACO

Xray structure of Blc dimer in complex with vaccenic acid


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.171 
  • R-Value Observed: 0.173 

Starting Model: experimental
View more details

wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 


This is version 1.3 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: https://doi.org/10.1016/j.febslet.2006.07.086
  • Primary Citation of Related Structures:  
    2ACO

  • 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 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-Universités Aix-Marseille I & II, Campus de Luminy, Case 932, 163 Avenue de Luminy, 13288 Marseille Cedex 09, France.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Outer membrane lipoprotein blc
A, B
173Escherichia coliMutation(s): 0 
Gene Names: blc
UniProt
Find proteins for P0A901 (Escherichia coli (strain K12))
Explore P0A901 
Go to UniProtKB:  P0A901
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A901
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
VCA
Query on VCA

Download Ideal Coordinates CCD File 
C [auth B]VACCENIC ACID
C18 H34 O2
UWHZIFQPPBDJPM-FPLPWBNLSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.171 
  • R-Value Observed: 0.173 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.901α = 90
b = 81.337β = 90
c = 89.02γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
CCP4data scaling
AMoREphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-08-01
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-23
    Changes: Data collection, Database references, Derived calculations, Refinement description