2O84

Crystal structure of K206E mutant of N-lobe human transferrin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.213 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Structures of two mutants that probe the role in iron release of the dilysine pair in the N-lobe of human transferrin.

Baker, H.M.Nurizzo, D.Mason, A.B.Baker, E.N.

(2007) Acta Crystallogr.,Sect.D 63: 408-414

  • DOI: 10.1107/S0907444907000182
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Iron uptake by humans depends on the ability of the serum protein transferrin (Tf) to bind iron as Fe(3+) with high affinity but reversibly. Iron release into cells occurs through receptor-mediated endocytosis, aided by the lower endosomal pH of abou ...

    Iron uptake by humans depends on the ability of the serum protein transferrin (Tf) to bind iron as Fe(3+) with high affinity but reversibly. Iron release into cells occurs through receptor-mediated endocytosis, aided by the lower endosomal pH of about 5.5. The protonation of a hydrogen-bonded pair of lysines, Lys206 and Lys296, adjacent to the N-lobe iron site of Tf has been proposed to create a repulsive interaction that stimulates domain opening and iron release. The crystal structures of two mutants, K206E (in which Lys206 is mutated to Glu) and K206E/K296E (in which both lysines are mutated to Glu), have been determined. The K206E structure (2.6 A resolution; R = 0.213, R(free) = 0.269) shows that a salt bridge is formed between Glu206 and Lys296, thus explaining the drastically slower iron release by this mutant. The K206E/K296E double-mutant structure (2.8 A resolution; R = 0.232, R(free) = 0.259) shows that the Glu296 side chain moves away from Glu206, easing any repulsive interaction and instead interacting with the iron ligand His249. The evident conformational flexibility is consistent with an alternative model for the operation of the dilysine pair in iron release in which it facilitates concerted proton transfer to the tyrosine ligand Tyr188 as one step in the weakening of iron binding.


    Organizational Affiliation

    School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Serotransferrin
X
337Homo sapiensMutation(s): 1 
Gene Names: TF
Find proteins for P02787 (Homo sapiens)
Go to Gene View: TF
Go to UniProtKB:  P02787
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K

Download SDF File 
Download CCD File 
X
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
FE
Query on FE

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

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.213 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 44.173α = 90.00
b = 57.317β = 90.00
c = 135.583γ = 90.00
Software Package:
Software NamePurpose
MAR345data collection
AMoREphasing
MOSFLMdata reduction
REFMACrefinement
SCALAdata scaling
PDB_EXTRACTdata extraction
CCP4data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-01-23
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-18
    Type: Refinement description