3ELZ

Crystal structure of Zebrafish Ileal Bile Acid-Bindin Protein complexed with cholic acid (crystal form A).


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.222 
  • R-Value Observed: 0.224 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

The X-Ray structure of zebrafish (Danio rerio) ileal bile acid-binding protein reveals the presence of binding sites on the surface of the protein molecule.

Capaldi, S.Saccomani, G.Fessas, D.Signorelli, M.Perduca, M.Monaco, H.L.

(2009) J Mol Biol 385: 99-116

  • DOI: https://doi.org/10.1016/j.jmb.2008.10.007
  • Primary Citation of Related Structures:  
    3ELX, 3ELZ, 3EM0

  • PubMed Abstract: 

    The ileal bile acid-binding proteins (I-BABPs), also called ileal lipid-binding proteins or gastrotropins, belong to the family of the fatty acid-binding proteins and play an important role in the solubilization and transport of bile acids in the enterocyte. This article describes the expression, purification, crystallization, and three-dimensional structure determination of zebrafish (Danio rerio) I-BABP both in its apo form and bound to cholic acid. This is the first X-ray structure of an I-BABP. The structure of the apoprotein was determined to a resolution of 1.6 A, and two different monoclinic crystal forms of the holoprotein were solved and refined to 2.2 A resolution. Three protein molecules are present in the asymmetric unit of one of the co-crystal forms and two in the other, and therefore, the results of this study refer to observations made on five different protein molecules in the crystalline state. In every case, two cholate ligands were found bound in approximately the same position in the internal cavity of the protein molecules, but an unexpected result is the presence of clear and unambiguous electron density for several cholate molecules bound on hydrophobic patches on the surface of all the five independent protein molecules examined. Isothermal titration calorimetry was used for the thermodynamic characterization of the binding mechanism and has yielded results that are consistent with the X-ray data. Ligand binding is described in detail, and the conformational changes undergone by the protein molecule in the apo-to-holo transition are examined by superposition of the apo- and holoprotein models. The structure of the holoprotein is also compared with that of the liver BABP from the same species and those of other I-BABPs determined by NMR.


  • Organizational Affiliation

    Biocrystallography Laboratory, Department of Biotechnology, University of Verona, Verona, Italy.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ileal Bile Acid-Binding Protein
A, B, C
138Danio rerioMutation(s): 0 
Gene Names: fabp6zgc:92421
Membrane Entity: Yes 
UniProt
Find proteins for Q6IMW5 (Danio rerio)
Explore Q6IMW5 
Go to UniProtKB:  Q6IMW5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ6IMW5
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
CHD
Query on CHD

Download Ideal Coordinates CCD File 
D [auth A]
E [auth A]
F [auth A]
G [auth A]
H [auth A]
D [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth B],
J [auth B],
K [auth B],
L [auth B],
M [auth B],
N [auth C],
O [auth C],
P [auth C]
CHOLIC ACID
C24 H40 O5
BHQCQFFYRZLCQQ-OELDTZBJSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.222 
  • R-Value Observed: 0.224 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 149.195α = 90
b = 80.29β = 96.12
c = 39.723γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
MOLREPphasing
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-01-13
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2023-09-06
    Changes: Data collection, Database references, Derived calculations, Refinement description