Bovine beta-lactoglobulin variant A at pH 4.0

Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.234 

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Revealing the Dimeric Crystal and Solution Structure of beta-Lactoglobulin at pH 4 and Its pH and Salt Dependent Monomer-Dimer Equilibrium.

Khan, S.Ipsen, R.Almdal, K.Svensson, B.Harris, P.

(2018) Biomacromolecules 19: 2905-2912

  • DOI: https://doi.org/10.1021/acs.biomac.8b00471
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The dimeric structure of bovine β-lactoglobulin A (BLGA) at pH 4.0 was solved to 2.0 Å resolution. Fitting the BLGA pH 4.0 structure to SAXS data at low ionic strength (goodness of fit R-factor = 3.6%) verified the dimeric state in solution. Analysis of the monomer-dimer equilibrium at varying pH and ionic strength by SAXS and scattering modeling showed that BLGA is dimeric at pH 3.0 and 4.0, shifting toward a monomer at pH 2.2, 2.6, and 7.0 yielding monomer/dimer ratios of 80/20%, 50/50%, and 25/75%, respectively. BLGA remained a dimer at pH 3.0 and 4.0 in 50-150 mM NaCl, whereas the electrostatic shielding raised the dimer content at pH 2.2, 2.6, and 7.0, i.e., below and above the pI. Overall, the findings provide new insights into the molecular characteristics of BLGA relevant for dairy product formulations and for various biotechnological and pharmaceutical applications.

  • Organizational Affiliation

    Enzyme and Protein Chemistry, Department of Biotechnology and Biomedicine , Technical University of Denmark , Søltofts Plads, Building 224 , DK-2800 Kgs. Lyngby , Denmark.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Major allergen beta-lactoglobulin
A, B, C, D
162Bos taurusMutation(s): 0 
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
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.234 
  • Space Group: P 2 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.11α = 90
b = 75.61β = 90
c = 140.62γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling
PDB_EXTRACTdata extraction

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Danish Research Council for Independent Research | Technical and Production SciencesDenmarkHEXPIN

Revision History  (Full details and data files)

  • Version 1.0: 2018-05-23
    Type: Initial release
  • Version 1.1: 2018-07-18
    Changes: Data collection, Database references
  • Version 1.2: 2019-02-20
    Changes: Advisory, Data collection, Derived calculations