4X0J

Trypanosoma brucei haptoglobin-haemoglobin receptor


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.199 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

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-e05553

  • DOI: 10.7554/eLife.05553
  • Primary Citation of Related Structures:  

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




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Haptoglobin-hemoglobin receptor
A, B
265Trypanosoma brucei bruceiMutation(s): 0 
Gene Names: HpHbR
Find proteins for I7BA99 (Trypanosoma brucei brucei)
Go to UniProtKB:  I7BA99
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.199 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 27.900α = 90.00
b = 47.790β = 92.79
c = 203.380γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
PHASERphasing
MOSFLMdata reduction
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-12-24
    Type: Initial release
  • Version 1.1: 2015-01-21
    Type: Database references
  • Version 1.2: 2015-03-04
    Type: Database references