6SNY

Synthetic mimic of an EPCR-binding PfEMP1 bound to EPCR


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.11 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.224 
  • R-Value Observed: 0.225 

wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 


This is version 2.1 of the entry. See complete history


Literature

Structure-Guided Design of a Synthetic Mimic of an Endothelial Protein C Receptor-Binding PfEMP1 Protein.

Barber, N.M.Lau, C.K.Y.Turner, L.Watson, G.Thrane, S.Lusingu, J.P.A.Lavstsen, T.Higgins, M.K.

(2021) mSphere 6

  • DOI: https://doi.org/10.1128/mSphere.01081-20
  • Primary Citation of Related Structures:  
    6SNY

  • PubMed Abstract: 

    Structure-guided vaccine design provides a route to elicit a focused immune response against the most functionally important regions of a pathogen surface. This can be achieved by identifying epitopes for neutralizing antibodies through structural methods and recapitulating these epitopes by grafting their core structural features onto smaller scaffolds. In this study, we conducted a modified version of this protocol. We focused on the PfEMP1 protein family found on the surfaces of erythrocytes infected with Plasmodium falciparum A subset of PfEMP1 proteins bind to endothelial protein C receptor (EPCR), and their expression correlates with development of the symptoms of severe malaria. Structural studies revealed that PfEMP1 molecules present a helix-kinked-helix motif that forms the core of the EPCR-binding site. Using Rosetta-based design, we successfully grafted this motif onto a three-helical bundle scaffold. We show that this synthetic binder interacts with EPCR with nanomolar affinity and adopts the expected structure. We also assessed its ability to bind to antibodies found in immunized animals and in humans from malaria-endemic regions. Finally, we tested the capacity of the synthetic binder to effectively elicit antibodies that prevent EPCR binding and analyzed the degree of cross-reactivity of these antibodies across a diverse repertoire of EPCR-binding PfEMP1 proteins. Despite our synthetic binder adopting the correct structure, we find that it is not as effective as the CIDRα domain on which it is based for inducing adhesion-inhibitory antibodies. This cautions against the rational design of focused immunogens that contain the core features of a ligand-binding site of a protein family, rather than those of a neutralizing antibody epitope. IMPORTANCE Vaccines train our immune systems to generate antibodies which recognize pathogens. Some of these antibodies are highly protective, preventing infection, while others are ineffective. Structure-guided rational approaches allow design of synthetic molecules which contain only the regions of a pathogen required to induce production of protective antibodies. On the surfaces of red blood cells infected by the malaria parasite Plasmodium falciparum are parasite molecules called PfEMP1 proteins. PfEMP1 proteins, which bind to human receptor EPCR, are linked to development of severe malaria. We have designed a synthetic protein on which we grafted the EPCR-binding surface of a PfEMP1 protein. We use this molecule to show which fraction of protective antibodies recognize the EPCR-binding surface and test its effectiveness as a vaccine immunogen.


  • Organizational Affiliation

    Centre for Medical Parasitology, Department of Infectious Diseases, University of Copenhagen, Copenhagen, Denmark.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Synthetic EPCR binding protein124synthetic constructMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
Expand
  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Endothelial protein C receptor
B, C
193Homo sapiensMutation(s): 0 
Gene Names: PROCREPCR
UniProt & NIH Common Fund Data Resources
Find proteins for Q9UNN8 (Homo sapiens)
Explore Q9UNN8 
Go to UniProtKB:  Q9UNN8
PHAROS:  Q9UNN8
GTEx:  ENSG00000101000 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9UNN8
Sequence Annotations
Expand
  • Reference Sequence
Oligosaccharides

Help

Entity ID: 3
MoleculeChains Length2D Diagram Glycosylation3D Interactions
alpha-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
D, F, H
3N-Glycosylation
Glycosylation Resources
GlyTouCan:  G62182OO
GlyCosmos:  G62182OO
GlyGen:  G62182OO
Entity ID: 4
MoleculeChains Length2D Diagram Glycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
E, G
2N-Glycosylation
Glycosylation Resources
GlyTouCan:  G42666HT
GlyCosmos:  G42666HT
GlyGen:  G42666HT
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.11 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.224 
  • R-Value Observed: 0.225 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 112.729α = 90
b = 112.729β = 90
c = 168.492γ = 120
Software Package:
Software NamePurpose
BUSTERrefinement
PDB_EXTRACTdata extraction
xia2data reduction
xia2data scaling
PHASERphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Wellcome Trust--

Revision History  (Full details and data files)

  • Version 1.0: 2019-09-04
    Type: Initial release
  • Version 1.1: 2020-03-18
    Changes: Data collection, Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary
  • Version 2.1: 2021-01-20
    Changes: Database references, Structure summary