1NNT

STRUCTURAL EVIDENCE FOR A PH-SENSITIVE DI-LYSINE TRIGGER IN THE HEN OVOTRANSFERRIN N-LOBE: IMPLICATIONS FOR TRANSFERRIN IRON RELEASE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Work: 0.160 
  • R-Value Observed: 0.160 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Structural evidence for a pH-sensitive dilysine trigger in the hen ovotransferrin N-lobe: implications for transferrin iron release.

Dewan, J.C.Mikami, B.Hirose, M.Sacchettini, J.C.

(1993) Biochemistry 32: 11963-11968

  • DOI: 10.1021/bi00096a004
  • Primary Citation of Related Structures:  
    1NNT

  • PubMed Abstract: 
  • Members of the transferrin family of proteins are involved in Fe3+ transport (serum transferrins) and are also believed to possess antimicrobial activity (ovotransferrins and lactoferrins). The structure of the monoferric N-terminal half-molecule of hen ovotransferrin, reported here at 2 ...

    Members of the transferrin family of proteins are involved in Fe3+ transport (serum transferrins) and are also believed to possess antimicrobial activity (ovotransferrins and lactoferrins). The structure of the monoferric N-terminal half-molecule of hen ovotransferrin, reported here at 2.3-A resolution, reveals an unusual interdomain interaction formed between the side-chain NZ atoms of Lys 209 and Lys 301, which are 2.3 A apart. This strong interaction appears to be an example of a low-barrier hydrogen bond between the two lysine NZ atoms, both of which are also involved in a hydrogen-bonding interaction with the aromatic ring of a tyrosine residue. Crystals of the protein were grown at pH 5.9, which is well below the usual pKa approximately 10 for a lysine side chain. We suggest that the pKa of either one or both of these residues lies below the pH of the structure determination and is, therefore, not positively charged. This finding may serve to explain, on a molecular basis, the pH dependence of transferrin Fe3+ release. We propose that uptake of the Fe(3+)-transferrin complex into an acidic endosome (viz., pH approximately 5.0) via receptor-mediated endocytosis will result in the protonation of both lysine residues. The close proximity of the two resulting positive charges, and their location on opposite domains of the N-lobe, might well be the driving force that opens the two domains of the protein, exposing the Fe3+ ion and facilitating its release.(ABSTRACT TRUNCATED AT 250 WORDS)


    Organizational Affiliation

    Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
OVOTRANSFERRINA328Gallus gallusMutation(s): 0 
UniProt
Find proteins for P02789 (Gallus gallus)
Explore P02789 
Go to UniProtKB:  P02789
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02789
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CO3
Query on CO3

Download Ideal Coordinates CCD File 
C [auth A]CARBONATE ION
C O3
BVKZGUZCCUSVTD-UHFFFAOYSA-L
 Ligand Interaction
FE
Query on FE

Download Ideal Coordinates CCD File 
B [auth A]FE (III) ION
Fe
VTLYFUHAOXGGBS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Work: 0.160 
  • R-Value Observed: 0.160 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 46.94α = 90
b = 91.79β = 90
c = 75.82γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
TNTrefinement
X-PLORrefinement
X-PLORphasing

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1994-10-15
    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: 2019-07-17
    Changes: Data collection, Other, Refinement description
  • Version 1.4: 2019-08-14
    Changes: Data collection, Refinement description