Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

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Protein Workshop | Ligand Explorer

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 37370.16 
• Atom Count: 2556 
• Residue Count: 337 
• Unique protein chains: 1

2O84

Crystal structure of K206E mutant of N-lobe human transferrin

• DOI: 10.2210/pdb2O84/pdb

• Classification: METAL TRANSPORT
• Organism(s): Homo sapiens
• Expression System: Mesocricetus auratus
• Mutation(s): 1 


• Deposited: 2006-12-12 Released: 2007-01-23 
• Deposition Author(s): Baker, H.M., Nurizzo, D., Mason, A.B., Baker, E.N.

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Experimental Data Snapshot

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

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

• PubMed: 17327678 
• DOI: 10.1107/S0907444907000182
• Primary Citation of Related Structures:  
  2O7U


• 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 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.

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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
Molecule	Chains	Sequence Length	Organism	Details
Serotransferrin	X	337	Homo sapiens	Mutation(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
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
K	X	POTASSIUM ION K NPYPAHLBTDXSSS-UHFFFAOYSA-N
FE	X	FE (III) ION Fe VTLYFUHAOXGGBS-UHFFFAOYSA-N
CO3	X	CARBONATE ION C O3 BVKZGUZCCUSVTD-UHFFFAOYSA-L

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 = 44.173	α = 90.00
b = 57.317	β = 90.00
c = 135.583	γ = 90.00

Software Package:

Software Name	Purpose
MAR345	data collection
AMoRE	phasing
MOSFLM	data reduction
REFMAC	refinement
SCALA	data scaling
PDB_EXTRACT	data extraction
CCP4	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2006-12-12 
• Released Date: 2007-01-23 
• Deposition Author(s): Baker, H.M., Nurizzo, D., Mason, A.B., Baker, E.N.

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