1DTG

HUMAN TRANSFERRIN N-LOBE MUTANT H249E


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.294 
  • R-Value Work: 0.198 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Mutation of the iron ligand His 249 to Glu in the N-lobe of human transferrin abolishes the dilysine "trigger" but does not significantly affect iron release.

MacGillivray, R.T.Bewley, M.C.Smith, C.A.He, Q.Y.Mason, A.B.

(2000) Biochemistry 39: 1211-1216


  • PubMed Abstract: 
  • Serum transferrin is the major iron transport protein in humans. Its function depends on its ability to bind iron with very high affinity, yet to release this bound iron at the lower intracellular pH. Possible explanations for the release of iron fro ...

    Serum transferrin is the major iron transport protein in humans. Its function depends on its ability to bind iron with very high affinity, yet to release this bound iron at the lower intracellular pH. Possible explanations for the release of iron from transferrin at low pH include protonation of a histidine ligand and the existence of a pH-sensitive "trigger" involving a hydrogen-bonded pair of lysines in the N-lobe of transferrin. We have determined the crystal structure of the His249Glu mutant of the N-lobe half-molecule of human transferrin and compared its iron-binding properties with those of the wild-type protein and other mutants. The crystal structure, determined at 2.4 A resolution (R-factor 19.8%, R(free) 29.4%), shows that Glu 249 is directly bound to iron, in place of the His ligand, and that a local movement of Lys 296 has broken the dilysine interaction. Despite the loss of this potentially pH-sensitive interaction, the H249E mutant is only slightly more acid-stable than wild-type and releases iron slightly faster. We conclude that the loss of the dilysine interaction does make the protein more acid stable but that this is counterbalanced by the replacement of a neutral ligand (His) by a negatively charged one (Glu), thus disrupting the electroneutrality of the binding site.


    Organizational Affiliation

    Department of Biochemistry, Massey University, Palmerston North, New Zealand.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
TRANSFERRIN
A
334Homo sapiensMutation(s): 1 
Gene Names: TF
Find proteins for P02787 (Homo sapiens)
Go to Gene View: TF
Go to UniProtKB:  P02787
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FE
Query on FE

Download SDF File 
Download CCD File 
A
FE (III) ION
Fe
VTLYFUHAOXGGBS-UHFFFAOYSA-N
 Ligand Interaction
CO3
Query on CO3

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.294 
  • R-Value Work: 0.198 
  • Space Group: P 41 21 2
Unit Cell:
Length (Å)Angle (°)
a = 72.660α = 90.00
b = 72.660β = 90.00
c = 152.490γ = 90.00
Software Package:
Software NamePurpose
X-PLORphasing
ROTAVATAdata reduction
X-PLORmodel building
X-PLORrefinement
ROTAVATAdata scaling
CCP4data scaling
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-01-21
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-04
    Type: Refinement description