4IBA

Bovine beta-lactoglobulin (isoform B) in complex with dodecyl sulphate (SDS)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.223 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

The differences in binding 12-carbon aliphatic ligands by bovine beta-lactoglobulin isoform A and B studied by isothermal titration calorimetry and X-ray crystallography

Loch, J.I.Bonarek, P.Polit, A.Swiatek, S.Dziedzicka-Wasylewska, M.Lewinski, K.

(2013) J Mol Recognit 26: 357-367

  • DOI: https://doi.org/10.1002/jmr.2280
  • Primary Citation of Related Structures:  
    4IB6, 4IB7, 4IB8, 4IB9, 4IBA

  • PubMed Abstract: 

    Isoforms A (LGB-A) and B (LGB-B) of bovine lactoglobulin, the milk protein, differ in positions 64 (D↔G) and 118 (V↔A). Interactions of LGB-A and LGB-B with sodium dodecyl sulfate (SDS), dodecyltrimethylammonium chloride (DTAC) and lauric acid (LA), 12-carbon ligands possessing differently charged polar groups, were investigated using isothermal titration calorimetry and X-ray crystallography, to study the proton linkage phenomenon and to distinguish between effects related to different isoforms and different ligand properties. The determined values of ΔS and ΔH revealed that for all ligands, binding is entropically driven. The contribution from enthalpy change is lower and shows strong dependence on type of buffer that indicates proton release from the protein varying with protein isoform and ligand type and involvement of LA and Asp64 (in isoform A) in this process. The ligand affinities for both isoforms were arranged in the same order, DTAC < LA < SDS, and were systematically lower for variant B. The entropy change of the complexation process was always higher for isoform A, but these values were compensated by changes in enthalpy, resulting in almost identical ΔG for complexes of both isoforms. The determined crystal structures showed that substitution in positions 64 and 118 did not influence the overall structure of LGB complexes. The chemical character of the ligand polar group did not affect the position of its aliphatic chain in protein β-barrel, indicating a major role of hydrophobic interactions in ligand binding that prevailed even with the repulsion between positively charged DTAC and lysine residues located at binding site entrance.


  • Organizational Affiliation

    Jagiellonian University, Faculty of Chemistry, Department of Crystal Chemistry and Crystal Physics, Ingardena 3, 30-060 Kraków, Poland.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
beta-lactoglobulin162Bos taurusMutation(s): 0 
UniProt
Find proteins for P02754 (Bos taurus)
Explore P02754 
Go to UniProtKB:  P02754
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02754
Sequence Annotations
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  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.223 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.43α = 90
b = 53.43β = 90
c = 111.5γ = 120
Software Package:
Software NamePurpose
CrysalisProdata collection
MOLREPphasing
REFMACrefinement
CrysalisProdata 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: 2013-06-26
    Type: Initial release
  • Version 1.1: 2013-07-17
    Changes: Database references
  • Version 1.2: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description