1DTZ

STRUCTURE OF CAMEL APO-LACTOFERRIN DEMONSTRATES ITS DUAL ROLE IN SEQUESTERING AND TRANSPORTING FERRIC IONS SIMULTANEOUSLY:CRYSTAL STRUCTURE OF CAMEL APO-LACTOFERRIN AT 2.6A RESOLUTION.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.65 Å
  • R-Value Free: 0.266 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Camel lactoferrin, a transferrin-cum-lactoferrin: crystal structure of camel apolactoferrin at 2.6 A resolution and structural basis of its dual role.

Khan, J.A.Kumar, P.Paramasivam, M.Yadav, R.S.Sahani, M.S.Sharma, S.Srinivasan, A.Singh, T.P.

(2001) J Mol Biol 309: 751-761

  • DOI: https://doi.org/10.1006/jmbi.2001.4692
  • Primary Citation of Related Structures:  
    1DTZ

  • PubMed Abstract: 

    Camel lactoferrin is the first protein from the transferrin superfamily that has been found to display the characteristic functions of iron binding and release of lactoferrin as well as transferrin simultaneously. It was remarkable to observe a wide pH demarcation in the release of iron from two lobes. It loses 50 % iron at pH 6.5 and the remaining 50 % iron is released only at pH values between 4.0 and 2.0. Furthermore, proteolytically generated N and C-lobes of camel lactoferrin showed that the C-lobe lost iron at pH 6.5, while the N-lobe lost it only at pH less than 4.0. In order to establish the structural basis of this striking observation, the purified camel apolactoferrin was crystallized. The crystals belong to monoclinic space group C2 with unit cell dimensions a=175.8 A, b=80.9 A, c=56.4 A, beta=92.4 degrees and Z=4. The structure has been determined by the molecular replacement method and refined to an R-factor of 0.198 (R-free=0.268) using all the data in the resolution range of 20.0-2.6 A. The overall structure of camel apolactoferrin folds into two lobes which contain four distinct domains. Both lobes adopt open conformations indicating wide distances between the iron binding residues in the native iron-free form of lactoferrin. The dispositions of various residues of the iron binding pocket of the N-lobe of camel apolactoferrin are similar to those of the N-lobe in human apolactoferrin, while the corresponding residues in the C-lobe show a striking similarity with those in the C-lobes of duck and hen apo-ovotransferrins. These observations indicate that the N-lobe of camel apolactoferrin is structurally very similar to the N-lobe of human apolactoferrin and the structure of the C-lobe of camel apolactoferrin matches closely with those of the hen and duck apo-ovotransferrins. These observations suggest that the iron binding and releasing behaviour of the N-lobe of camel lactoferrin is similar to that of the N-lobe of human lactoferrin, whereas that of the C-lobe resembles those of the C-lobes of duck and hen apo-ovotransferrins. Hence, it correlates with the observation of the N-lobe of camel lactoferrin losing iron at a low pH (4.0-2.0) as in other lactoferrins. On the other hand, the C-lobe of camel lactoferrin loses iron at higher pH (7.0-6.0) like transferrins suggesting its functional similarity to that of transferrins. Thus, camel lactoferrin can be termed as half lactoferrin and half transferrin.


  • Organizational Affiliation

    Department of Biophysics, All India Institute of Medical Sciences, New Delhi, 110029, India.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
APO LACTOFERRIN689Camelus dromedariusMutation(s): 0 
UniProt
Find proteins for Q9TUM0 (Camelus dromedarius)
Explore Q9TUM0 
Go to UniProtKB:  Q9TUM0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9TUM0
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.65 Å
  • R-Value Free: 0.266 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 175.84α = 90
b = 80.92β = 92.35
c = 56.35γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing
CNSrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-06-20
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance