1F6S

CRYSTAL STRUCTURE OF BOVINE ALPHA-LACTALBUMIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.216 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structures of apo- and holo-bovine alpha-lactalbumin at 2. 2-A resolution reveal an effect of calcium on inter-lobe interactions.

Chrysina, E.D.Brew, K.Acharya, K.R.

(2000) J.Biol.Chem. 275: 37021-37029

  • DOI: 10.1074/jbc.M004752200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • High affinity binding of Ca(2+) to alpha-lactalbumin (LA) stabilizes the native structure and is required for the efficient generation of native protein with correct disulfide bonds from the reduced denatured state. A progressive increase in affinity ...

    High affinity binding of Ca(2+) to alpha-lactalbumin (LA) stabilizes the native structure and is required for the efficient generation of native protein with correct disulfide bonds from the reduced denatured state. A progressive increase in affinity of LA conformers for Ca(2+) as they develop increasingly native structures can account for the tendency of the apo form to assume a molten globule state and the large acceleration of folding by Ca(2+). To investigate the effect of calcium on structure of bovine LA, x-ray structures have been determined for crystals of the apo and holo forms at 2.2-A resolution. In both crystal forms, which were grown at high ionic strength, the protein is in a similar global native conformation consisting of alpha-helical and beta-subdomains separated by a cleft. Even though alternative cations and Ca(2+) liganding solvent molecules are absent, removal of Ca(2+) has only minor effects on the structure of the metal-binding site and a structural change was observed in the cleft on the opposite face of the molecule adjoining Tyr(103) of the helical lobe and Gln(54) of the beta-lobe. Changes include increased separation of the lobes, loss of a buried solvent molecule near the Ca(2+)-binding site, and the replacement of inter- and intra-lobe H-bonds of Tyr(103) by interactions with new immobilized water molecules. The more open cleft structure in the apo protein appears to be an effect of calcium binding transmitted via a change in orientation of helix H3 relative to the beta-lobe to the inter-lobe interface. Calcium is well known to promote the folding of LA. The results from the comparison of apo and holo structures of LA provide high resolution structural evidence that the acceleration of folding by Ca(2+) is mediated by an effect on interactions between the two subdomains.


    Related Citations: 
    • Structural Evidence for the Presence of a Secondary Calcium Binding Site in Human alpha-Lactalbumin
      Chandra, N.,Brew, K.,Acharya, K.R.
      (1998) Biochemistry 37: 4767
    • Refined Structure of Baboon alpha-Lactalbumin at 1.7 A Resolution. Comparison with C-type Lysozyme
      Acharya, K.R.,Stuart, D.I.,Walker, N.P.,Lewis, M.,Phillips, D.C.
      (1989) J.Mol.Biol. 208: 99
    • Crystal Structures of Guinea-pig, Goat and Bovine alpha-Lactalbumin Highlight the Enhanced Conformational Flexibility of Regions that are Significant for its Action in Lactose Synthase
      Pike, A.C.,Brew, K.,Acharya, K.R.
      (1996) Structure 4: 691
    • Crystal Structure of Human alpha-Lactalbumin at 1.7 A Resolution
      Acharya, K.R.,Ren, J.S.,Stuart, D.I.,Phillips, D.C.,Fenna, R.E.
      (1991) J.Mol.Biol. 221: 571
    • Alpha-Lactalbumin Possesses a Novel Calcium-Binding Loop
      Stuart, D.I.,Acharya, K.R.,Walker, N.P.,Smith, S.G.,Lewis, M.,Phillips, D.C.
      (1986) Nature 324: 84


    Organizational Affiliation

    Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ALPHA-LACTALBUMIN
A, B, C, D, E, F
123Bos taurusMutation(s): 0 
Gene Names: LALBA (ALACTA)
Find proteins for P00711 (Bos taurus)
Go to Gene View: LALBA
Go to UniProtKB:  P00711
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A, B, C, D, E, F
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.216 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 72.045α = 90.00
b = 104.650β = 90.00
c = 117.415γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
CNSrefinement
SCALEPACKdata scaling
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-12-13
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance