The structure of bovine B-lactoglobulin A in crystals grown at very low ionic strength

Experimental Data Snapshot

  • Resolution: 3.00 Å
  • R-Value Free: 0.266 
  • R-Value Work: 0.224 
  • R-Value Observed: 0.214 

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Structure of bovine beta-lactoglobulin (variant A) at very low ionic strength

Adams, J.J.Anderson, B.F.Norris, G.E.Creamer, L.K.Jameson, G.B.

(2006) J Struct Biol 154: 246-254

  • DOI: https://doi.org/10.1016/j.jsb.2005.12.010
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Bovine beta-lactoglobulin (BLG) is a globular protein of uncertain physiological function and a member of the lipocalin superfamily of proteins. Here, we present the X-ray structure at 3.0 angstroms of BLG (variant A) from an orthorhombic (P2(1)2(1)2(1)) pseudo-tetragonal crystal form that suffers from pseudo-merohedral twinning (final R(working) = 0.224, R(free) = 0.265). Crystals were grown by dialysis against ultra-purified water (i.e., at very low ionic strength), at pH approximately 5.2 (approximately pI), conditions vastly different from all other BLG structures determined previously. This allows critical assessment of the BLG structure and of the influence that pH, ionic strength, and crystal packing may have on the molecular structure of BLG. The pH-sensitive EF loop is found in the closed conformation characteristic of BLG at pH less than 7 and moderate to high ionic strength. Although the hydrophobic pocket appears to be empty, the presence of highly disordered water molecules cannot be excluded. The dimer interface and the hydrophobic pocket (calyx) are preserved. However, the orientation of the subunits in the dimer varies considerably with crystal form. Structure is deposited with PDB ID 2akq.

  • Organizational Affiliation

    Centre for Structural Biology, Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Beta-lactoglobulin variant A
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: 3.00 Å
  • R-Value Free: 0.266 
  • R-Value Work: 0.224 
  • R-Value Observed: 0.214 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 68.191α = 90
b = 68.231β = 90
c = 131.455γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-08-16
    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: 2023-10-25
    Changes: Data collection, Database references, Refinement description