1SDX

Crystal structure of the zinc saturated C-terminal half of bovine lactoferrin at 2.0 A resolution reveals two additional zinc binding sites


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.06 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.192 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Structure of the zinc-saturated C-terminal lobe of bovine lactoferrin at 2.0 A resolution.

Jabeen, T.Sharma, S.Singh, N.Bhushan, A.Singh, T.P.

(2005) Acta Crystallogr D Biol Crystallogr 61: 1107-1115

  • DOI: 10.1107/S0907444905016069
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • The crystal structure of the zinc-saturated C-terminal lobe of bovine lactoferrin has been determined at 2.0 A resolution using crystals stabilized at pH 3.8. This is the first metal-saturated structure of any functional lactoferrin at such a low pH. ...

    The crystal structure of the zinc-saturated C-terminal lobe of bovine lactoferrin has been determined at 2.0 A resolution using crystals stabilized at pH 3.8. This is the first metal-saturated structure of any functional lactoferrin at such a low pH. Purified samples of proteolytically generated zinc-saturated C-terminal lobe were crystallized from 0.1 M MES buffer pH 6.5 containing 25%(v/v) polyethyleneglycol monomethyl ether 550 and 0.1 M zinc sulfate heptahydrate. The crystals were transferred to 25 mM ammonium acetate buffer containing 25%(v/v) polyethyleneglycol monomethyl ether 550 and the pH was gradually changed from 6.5 to 3.8. The X-ray intensity data were collected with a 345 mm imaging-plate scanner mounted on an RU-300 rotating-anode X-ray generator using crystals soaked in the buffer at pH 3.8. The structure was determined with the molecular-replacement method using the coordinates of the monoferric C-terminal lobe of bovine lactoferrin as a search model and was refined to an R factor of 0.192 for all data to 2.0 A resolution. The final model comprises 2593 protein atoms (residues 342-676 and 681-685), 138 carbohydrate atoms (from 11 monosaccharide units in three glycan chains), three Zn2+ ions, one CO3(2-) ion, one SO(4)2- ions and 227 water molecules. The overall folding of the present structure is essentially similar to that of the monoferric C-terminal lobe of bovine lactoferrin, although it contains Zn2+ in place of Fe3+ in the metal-binding cleft as well as two additional Zn2+ ions on the surface of the C-terminal lobe. The Zn2+ ion in the cleft remains bound to the lobe with octahedral coordination. The bidentate carbonate ion is stabilized by a network of hydrogen bonds to Ala465, Gly466, Thr459 and Arg463. The other two zinc ions also form sixfold coordinations involving symmetry-related protein and water molecules. The number of monosaccharide residues from the three glycan chains of the C-terminal lobe was 11, which is the largest number observed to date. The structure shows that the C-terminal lobe of lactoferrin is capable of sequestering a Zn2+ ion at a pH of 3.8. This implies that the zinc ions can be sequestered over a wide pH range. The glycan chain attached to Asn545 may also have some influence on iron release from the C-terminal lobe.


    Organizational Affiliation

    Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110 029, India.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Lactotransferrin
A
335Bos taurusMutation(s): 0 
Gene Names: LTF
EC: 3.4.21
Find proteins for P24627 (Bos taurus)
Go to UniProtKB:  P24627
  • Find similar proteins by: Sequence   |   Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Lactotransferrin
E
5Bos taurusMutation(s): 0 
Gene Names: LTF
EC: 3.4.21
Find proteins for P24627 (Bos taurus)
Go to UniProtKB:  P24627
Small Molecules
Ligands 7 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download CCD File 
A
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
NDG
Query on NDG

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A
2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE
C8 H15 N O6
OVRNDRQMDRJTHS-PVFLNQBWSA-N
 Ligand Interaction
BMA
Query on BMA

Download CCD File 
A
BETA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-RWOPYEJCSA-N
 Ligand Interaction
MAN
Query on MAN

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A
ALPHA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-PQMKYFCFSA-N
 Ligand Interaction
SO4
Query on SO4

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A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
ZN
Query on ZN

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A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
CO3
Query on CO3

Download CCD File 
A
CARBONATE ION
C O3
BVKZGUZCCUSVTD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.06 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.192 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 63.21α = 90
b = 50.57β = 107.64
c = 66.17γ = 90
Software Package:
Software NamePurpose
CNSrefinement
MAR345data collection
SCALEPACKdata scaling
AMoREphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-03-02
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description