2GJ5

Crystal structure of a secondary vitamin D3 binding site of milk beta-lactoglobulin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.298 
  • R-Value Work: 0.236 
  • R-Value Observed: 0.241 

wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Crystal structure of a secondary vitamin D3 binding site of milk beta-lactoglobulin.

Yang, M.C.Guan, H.H.Liu, M.Y.Lin, Y.H.Yang, J.M.Chen, W.L.Chen, C.J.Mao, S.J.

(2008) Proteins 71: 1197-1210

  • DOI: https://doi.org/10.1002/prot.21811
  • Primary Citation of Related Structures:  
    2GJ5

  • PubMed Abstract: 

    Beta-lactoglobulin (beta-LG), one of the most investigated proteins, is a major bovine milk protein with a predominantly beta structure. The structural function of the only alpha-helix with three turns at the C-terminus is unknown. Vitamin D(3) binds to the central calyx formed by the beta-strands. Whether there are two vitamin D binding-sites in each beta-LG molecule has been a subject of controversy. Here, we report a second vitamin D(3) binding site identified by synchrotron X-ray diffraction (at 2.4 A resolution). In the central calyx binding mode, the aliphatic tail of vitamin D(3) clearly inserts into the binding cavity, where the 3-OH group of vitamin D(3) binds externally. The electron density map suggests that the 3-OH group interacts with the carbonyl of Lys-60 forming a hydrogen bond (2.97 A). The second binding site, however, is near the surface at the C-terminus (residues 136-149) containing part of an alpha-helix and a beta-strand I with 17.91 A in length, while the span of vitamin D(3) is about 12.51 A. A remarkable feature of the second exosite is that it combines an amphipathic alpha-helix providing nonpolar residues (Phe-136, Ala-139, and Leu-140) and a beta-strand providing a nonpolar (Ile-147) and a buried polar residue (Arg-148). They are linked by a hydrophobic loop (Ala-142, Leu-143, Pro-144, and Met-145). Thus, the binding pocket furnishes strong hydrophobic force to stabilize vitamin D(3) binding. This finding provides a new insight into the interaction between vitamin D(3) and beta-LG, in which the exosite may provide another route for the transport of vitamin D(3) in vitamin D(3) fortified dairy products. Atomic coordinates for the crystal structure of beta-LG-vitamin D(3) complex described in this work have been deposited in the PDB (access code 2GJ5).


  • Organizational Affiliation

    Department of Biological Science and Technology, College of Biological Science and Technology, National Chiao Tung University, Taiwan, Republic of China.


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
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
VD3
Query on VD3

Download Ideal Coordinates CCD File 
B [auth A],
C [auth A]
(1S,3Z)-3-[(2E)-2-[(1R,3AR,7AS)-7A-METHYL-1-[(2R)-6-METHYLHEPTAN-2-YL]-2,3,3A,5,6,7-HEXAHYDRO-1H-INDEN-4-YLIDENE]ETHYLI DENE]-4-METHYLIDENE-CYCLOHEXAN-1-OL
C27 H44 O
QYSXJUFSXHHAJI-RWDMXNMGSA-N
Binding Affinity Annotations 
IDSourceBinding Affinity
VD3 Binding MOAD:  2GJ5 Kd: 4.74 (nM) from 1 assay(s)
PDBBind:  2GJ5 Kd: 4.74 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.298 
  • R-Value Work: 0.236 
  • R-Value Observed: 0.241 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.782α = 90
b = 53.782β = 90
c = 111.578γ = 120
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data reduction
CNSrefinement
HKL-2000data scaling
CNSphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-10-02
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-10-25
    Changes: Data collection, Database references, Derived calculations, Refinement description, Structure summary