5HU6

Structure of the T. brucei haptoglobin-haemoglobin receptor bound to human haptolgobin-haemoglobin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.9 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.190 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Re-refinement Note

This entry reflects an alternative modeling of the original data in: 

  • 4X0I - determined by Lane-Serff, H., MacGregor, P., Lowe, E.D., Carrington, M., Higgins, M.K.  

Literature

Structural basis for ligand and innate immunity factor uptake by the trypanosome haptoglobin-haemoglobin receptor.

Lane-Serff, H.MacGregor, P.Lowe, E.D.Carrington, M.Higgins, M.K.

(2014) Elife 3: e05553

  • DOI: 10.7554/eLife.05553
  • Primary Citation of Related Structures:  4X0I, 4X0J, 4X0L

  • PubMed Abstract: 
  • The haptoglobin-haemoglobin receptor (HpHbR) of African trypanosomes allows acquisition of haem and provides an uptake route for trypanolytic factor-1, a mediator of innate immunity against trypanosome infection. In this study, we report the structur ...

    The haptoglobin-haemoglobin receptor (HpHbR) of African trypanosomes allows acquisition of haem and provides an uptake route for trypanolytic factor-1, a mediator of innate immunity against trypanosome infection. In this study, we report the structure of Trypanosoma brucei HpHbR in complex with human haptoglobin-haemoglobin (HpHb), revealing an elongated ligand-binding site that extends along its membrane distal half. This contacts haptoglobin and the β-subunit of haemoglobin, showing how the receptor selectively binds HpHb over individual components. Lateral mobility of the glycosylphosphatidylinositol-anchored HpHbR, and a ∼50° kink in the receptor, allows two receptors to simultaneously bind one HpHb dimer. Indeed, trypanosomes take up dimeric HpHb at significantly lower concentrations than monomeric HpHb, due to increased ligand avidity that comes from bivalent binding. The structure therefore reveals the molecular basis for ligand and innate immunity factor uptake by trypanosomes and identifies adaptations that allow efficient ligand uptake in the context of the complex trypanosome cell surface.


    Organizational Affiliation

    Department of Biochemistry, University of Oxford, Oxford, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Hemoglobin subunit alpha
A
141Homo sapiensGene Names: HBA1, HBA2
Find proteins for P69905 (Homo sapiens)
Go to Gene View: HBA1 HBA2
Go to UniProtKB:  P69905
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Hemoglobin subunit beta
B
141Homo sapiensGene Names: HBB
Find proteins for P68871 (Homo sapiens)
Go to Gene View: HBB
Go to UniProtKB:  P68871
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
Haptoglobin
C
259Homo sapiensGene Names: HP
Find proteins for P00738 (Homo sapiens)
Go to Gene View: HP
Go to UniProtKB:  P00738
Entity ID: 4
MoleculeChainsSequence LengthOrganismDetails
Haptoglobin-hemoglobin receptor
D
260Trypanosoma brucei brucei (strain 927/4 GUTat10.1)N/A
Find proteins for Q581F2 (Trypanosoma brucei brucei (strain 927/4 GUTat10.1))
Go to UniProtKB:  Q581F2
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
OXY
Query on OXY

Download SDF File 
Download CCD File 
A, B
OXYGEN MOLECULE
O2
MYMOFIZGZYHOMD-UHFFFAOYSA-N
 Ligand Interaction
HEM
Query on HEM

Download SDF File 
Download CCD File 
A, B
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
NAG
Query on NAG

Download SDF File 
Download CCD File 
C
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.9 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.190 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 222.290α = 90.00
b = 56.560β = 92.97
c = 66.100γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
BUSTERrefinement
PHASERphasing
iMOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2016-03-02
    Type: Initial release