5IIU

Crystal structure of Equine Serum Albumin in the presence of 10 mM zinc at pH 6.9


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.179 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Circulatory zinc transport is controlled by distinct interdomain sites on mammalian albumins.

Handing, K.B.Shabalin, I.G.Kassaar, O.Khazaipoul, S.Blindauer, C.A.Stewart, A.J.Chruszcz, M.Minor, W.

(2016) Chem Sci 7: 6635-6648

  • DOI: 10.1039/c6sc02267g
  • Primary Citation of Related Structures:  5IIH, 5IIX, 5IJ5, 5IJE, 5IJF

  • PubMed Abstract: 
  • Zinc is an essential nutrient in the body; it is required for the catalytic activity of many hundreds of human enzymes and virtually all biological processes, therefore its homeostasis and trafficking is of crucial interest. Serum albumin is the majo ...

    Zinc is an essential nutrient in the body; it is required for the catalytic activity of many hundreds of human enzymes and virtually all biological processes, therefore its homeostasis and trafficking is of crucial interest. Serum albumin is the major carrier of Zn2+ in the blood and is required for its systemic distribution. Here we present the first crystal structures of human serum albumin (HSA) and equine serum albumin (ESA) in complex with Zn2+. The structures allow unambiguous identification of the major zinc binding site on these two albumins, as well as several further, weaker zinc binding sites. The major site in both HSA and ESA has tetrahedral geometry and comprises three protein ligands from the sidechains of His67, His247 and Asp249 and a water molecule. Isothermal titration calorimetric studies of a HSA H67A mutant confirm this to be the highest affinity Zn2+ site. Furthermore, analysis of Zn2+ binding to HSA and ESA proved the presence of secondary sites with 20-50-fold weaker affinities, which may become of importance under particular physiological conditions. Both calorimetry and crystallography suggest that ESA possesses an additional site compared to HSA, involving Glu153, His157 and His288. The His157 residue is replaced by Phe in HSA, incapable of metal coordination. Collectively, these findings are critical to our understanding of the role serum albumin plays in circulatory Zn2+ handling and cellular delivery.


    Organizational Affiliation

    Department of Molecular Physiology and Biological Physics , University of Virginia School of Medicine , PO Box 800736 , Charlottesville , VA 22908-0736 , USA . Email: wladek@iwonka.med.virginia.edu ; Tel: +1-434-243-6865.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Serum albumin
A
583Equus caballusGene Names: ALB
Find proteins for P35747 (Equus caballus)
Go to Gene View: ALB
Go to UniProtKB:  P35747
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

Unit Cell:
Length (Å)Angle (°)
a = 93.746α = 90.00
b = 93.746β = 90.00
c = 141.789γ = 120.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
SCALEPACKdata scaling
REFMACrefinement
MD2data collection
HKL-3000data reduction
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationCountryGrant Number
National Institutes of HealthUnited States--

Revision History 

  • Version 1.0: 2016-03-23
    Type: Initial release
  • Version 1.1: 2017-09-20
    Type: Author supporting evidence, Derived calculations
  • Version 1.2: 2017-12-13
    Type: Database references