8C27 | pdb_00008c27

Domain 3 of Group B Streptococcus pilus protein as scaffold for the display of foreign epitopes


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.63 Å
  • R-Value Free: 
    0.279 (Depositor), 0.281 (DCC) 
  • R-Value Work: 
    0.227 (Depositor), 0.220 (DCC) 
  • R-Value Observed: 
    0.229 (Depositor) 

Starting Model: experimental
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wwPDB Validation 3D Report Full Report

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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history

Literature

Computational structure-based approach to study chimeric antigens using a new protein scaffold displaying foreign epitopes.

Cappelli, L.Cinelli, P.Perrotta, A.Veggi, D.Audagnotto, M.Tuscano, G.Pansegrau, W.Bartolini, E.Rinaudo, D.Cozzi, R.

(2024) FASEB J 38: e23326-e23326

  • DOI: https://doi.org/10.1096/fj.202202130R
  • Primary Citation Related Structures: 
    8C27

  • PubMed Abstract: 

    The identification and recombinant production of functional antigens and/or epitopes of pathogens represent a crucial step for the development of an effective protein-based vaccine. Many vaccine targets are outer membrane proteins anchored into the lipidic bilayer through an extended hydrophobic portion making their recombinant production challenging. Moreover, only the extracellular loops, and not the hydrophobic regions, are naturally exposed to the immune system. In this work, the Domain 3 (D3) from Group B Streptococcus (GBS) pilus 2a backbone protein has been identified and engineered to be used as a scaffold for the display of extracellular loops of two Neisseria gonorrhoeae membrane proteins (PorB.1b and OpaB). A computational structure-based approach has been applied to the design of both the scaffold and the model antigens. Once identified the best D3 engineerable site, several different chimeric D3 displaying PorB.1b and OpaB extracellular loops were produced as soluble proteins. Each molecule has been characterized in terms of solubility, stability, and ability to correctly display the foreign epitope. This antigen dissection strategy allowed the identification of most immunogenic extracellular loops of both PorB.1b and OpaB gonococcal antigens. The crystal structure of chimeric D3 displaying PorB.1b immunodominant loop has been obtained confirming that the engineerization did not alter the predicted native structure of this epitope. Taken together, the reported data suggest that D3 is a novel protein scaffold for epitope insertion and display, and a valid alternative to the production of whole membrane protein antigens. Finally, this work describes a generalized computational structure-based approach for the identification, design, and dissection of epitopes in target antigens through chimeric proteins.


  • Organizational Affiliation
    • Dipartimento di Farmacia e Biotecnologie - FaBiT, University of Bologna, Bologna, Italy.

Macromolecule Content 

  • Total Structure Weight: 29.46 kDa 
  • Atom Count: 2,023 
  • Modeled Residue Count: 255 
  • Deposited Residue Count: 262 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
PI-2a backbone protein
A, B
131Streptococcus agalactiaeMutation(s): 0 
UniProt
Find proteins for B9UR22 (Streptococcus agalactiae)
Explore B9UR22 
Go to UniProtKB:  B9UR22
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupB9UR22
Sequence Annotations
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Reference Sequence

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.63 Å
  • R-Value Free:  0.279 (Depositor), 0.281 (DCC) 
  • R-Value Work:  0.227 (Depositor), 0.220 (DCC) 
  • R-Value Observed: 0.229 (Depositor) 
Space Group: F 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 71.391α = 90
b = 118.047β = 90
c = 189.815γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
PHENIXrefinement
XDSdata reduction
autoPROCdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2024-01-10
    Type: Initial release
  • Version 1.1: 2024-07-24
    Changes: Database references