Experimental Data Snapshot

  • Resolution: 1.60 Å
  • R-Value Work: 0.181 

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Two high-resolution crystal structures of the recombinant N-lobe of human transferrin reveal a structural change implicated in iron release.

MacGillivray, R.T.Moore, S.A.Chen, J.Anderson, B.F.Baker, H.Luo, Y.Bewley, M.Smith, C.A.Murphy, M.E.Wang, Y.Mason, A.B.Woodworth, R.C.Brayer, G.D.Baker, E.N.

(1998) Biochemistry 37: 7919-7928

  • DOI: https://doi.org/10.1021/bi980355j
  • Primary Citation of Related Structures:  
    1A8E, 1A8F

  • PubMed Abstract: 

    The N-lobe of human serum transferrin (hTF/2N) has been expressed in baby hamster kidney cells and crystallized in both orthorhombic (P212121) and tetragonal (P41212) space groups. Both crystal forms diffract to high resolution (1.6 and 1.8 A, respectively) and have been solved by molecular replacement. Subsequent refinement resulted in final models for the structure of hTF/2N that had crystallographic R-factors of 18.1 and 19.7% for the two crystal forms, respectively; these models represent the highest-resolution transferrin structures determined to date. The hTF/2N polypeptide has a folding pattern similar to those of other transferrins, including the presence of a deep cleft that contains the metal-binding site. In contrast to other transferrins, both crystal forms of hTF/2N display disorder at the iron-binding site; model building suggests that this disorder consists of alternative conformations of the synergistically bound carbonate anion, the side chain for Arg-124, and several solvent molecules. Subsequent refinement revealed that conformation A has an occupancy of 0.63-0. 65 and corresponds to the structure of the iron-binding site found in other transferrins. The alternative conformation B has an occupancy of 0.35-0.37; in this structure, the carbonate has rotated 30 degrees relative to the iron and the side chain for Arg-124 has moved to accommodate the new carbonate position. Several water molecules appear to stabilize the carbonate anion in the two conformations. These structures are consistent with the protonation of the carbonate and resulting partial removal of the anion from the metal; these events would occur prior to cleft opening and metal release.

  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada. macg@unixg.ubc.ca

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
SERUM TRANSFERRIN329Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P02787 (Homo sapiens)
Explore P02787 
Go to UniProtKB:  P02787
PHAROS:  P02787
GTEx:  ENSG00000091513 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02787
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.60 Å
  • R-Value Work: 0.181 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.12α = 90
b = 57.91β = 90
c = 135.64γ = 90
Software Package:
Software NamePurpose
R-AXISdata collection
R-AXISdata reduction
R-AXISdata scaling

Structure Validation

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Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 1998-06-17
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-04-03
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description