Experimental Data Snapshot

  • Resolution: 1.80 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.181 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


Bovine beta-lactoglobulin at 1.8 A resolution--still an enigmatic lipocalin.

Brownlow, S.Morais Cabral, J.H.Cooper, R.Flower, D.R.Yewdall, S.J.Polikarpov, I.North, A.C.Sawyer, L.

(1997) Structure 5: 481-495

  • DOI: https://doi.org/10.1016/s0969-2126(97)00205-0
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    beta-Lactoglobulin (beta-Lg) is the major whey protein in the milk of ruminants and many other mammals. Its function is not known, but it undergoes at least two pH-dependent conformational changes which may be important. Bovine beta-Lg crystallizes in several different lattices, and medium-resolution structures of orthorhombic lattice Y and trigonal lattice Z have been published. Triclinic lattice X and lattice Z crystals grow at pH values either side of the pH at which one of the pH-induced conformational changes occurs. A full understanding of the structure is needed to help explain both the conformational changes and the different denaturation behaviour of the genetic variants. We have redetermined the structure of beta-Lg lattice Z at 3.0 A resolution by multiple isomorphous replacement and have partially refined it (R factor = 24.8%). Using the dimer from this lattice Z structure as a search model, the triclinic crystal form grown at pH 6.5 (lattice X) has been solved by molecular replacement. Refinement of lattice X at 1.8 A resolution gave an R factor of 18.1%. The structure we have determined differs from previously published structures in several ways. Incorrect threading of the sequence in the published structures of beta-Lg affects four of the nine beta strands. The basic lipocalin fold of the polypeptide chain is unchanged, however. The relative orientation of the monomers in the beta-Lg dimer differs in the two lattices. On raising the pH, there is a rotation of approximately 5 degrees, which breaks a number of intersubunit hydrogen bonds. It is not yet clear, however, why the stability of the structure should depend so heavily upon the external loop around residue 64 or the beta strand with the free thiol, each of which shows genetic variation.

  • Organizational Affiliation

    Leeds Centre for Molecular Recognition in Biological Systems, Department of Biochemistry and Molecular Biology, The University of Leeds, Leeds, LS2 9JT, UK.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
162Bos taurusMutation(s): 1 
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
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on SO4

Download Ideal Coordinates CCD File 
O4 S
Experimental Data & Validation

Experimental Data

  • Resolution: 1.80 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.181 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 37.8α = 123.4
b = 49.5β = 97.3
c = 56.6γ = 103.7
Software Package:
Software NamePurpose
XDSdata scaling
ROTAVATAdata reduction
Agrovatadata reduction
X-PLORmodel building
XDSdata reduction
CCP4data scaling
ROTAVATAdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-05-15
    Type: Initial release
  • Version 1.1: 2008-03-03
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-04-03
    Changes: Data collection, Database references, Derived calculations, Refinement description