9MN2 | pdb_00009mn2

Crystal Structure of the B6C Region of the Group B Streptococcus Beta Antigen C Protein


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.05 Å
  • R-Value Free: 
    0.274 (Depositor), 0.275 (DCC) 
  • R-Value Work: 
    0.243 (Depositor), 0.244 (DCC) 
  • R-Value Observed: 
    0.246 (Depositor) 

wwPDB Validation 3D Report Full Report

Validation slider image for 9MN2

This is version 1.1 of the entry. See complete history

Literature

Bacterial targeting of the neutrophil inhibitory receptor LILRB3 to evade antibody immunity.

Rumpret, M.Lewis Marffy, A.L.Zhang, Y.van Woudenbergh, E.van der Lans, S.P.A.Xu, X.Fu, Z.Zhao, Y.Catton, E.A.Pare, G.McGregor, F.Spiller, O.B.Fernandes, M.J.de Haas, C.J.C.van Strijp, J.A.G.van Sorge, N.M.Geisbrecht, B.V.McCarthy, A.J.

(2026) Nat Commun 17

  • DOI: https://doi.org/10.1038/s41467-026-74098-6
  • Primary Citation Related Structures: 
    9MN2

  • PubMed Abstract: 

    Antibody-mediated responses are critical for antibacterial immunity, driving Fc receptor-mediated phagocytosis, respiratory burst, and bacterial killing. Inhibitory immune receptors regulate cellular activation and immune homoeostasis, but whether they are targeted to evade antibody-mediated responses is unclear. Here, we show that the highly expressed inhibitory LILRB3 receptor on neutrophils is targeted by Streptococcus agalactiae to suppress antibody-driven defence. We show that the surface-localised β protein of S. agalactiae bound to LILRB3 and induced its cross-linking. β and LILRB3 interactions suppressed Fc receptor-mediated antibacterial responses such as respiratory burst and bacterial killing, inhibiting antibody-dependent bacterial killing by neutrophils. Moreover, β expression and LILRB3 targeting are associated with S. agalactiae lineages that cause invasive diseases in older adults, indicating that targeting inhibitory receptors most likely provides an immune evasion mechanism when antibody responses are waning, such as in immunocompromised or elderly individuals. Altogether, these results highlight a simple and important mechanism that bacterial pathogens utilise to overcome effective antibody-driven phagocyte responses.


  • Organizational Affiliation
    • Centre for Bacterial Resistance Biology (CBRB), Department of Infectious Disease, Imperial College London, London, UK.

Macromolecule Content 

  • Total Structure Weight: 39.88 kDa 
  • Atom Count: 2,558 
  • Modeled Residue Count: 307 
  • Deposited Residue Count: 344 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
IgA FC receptor
A, B
172Streptococcus agalactiaeMutation(s): 0 
Gene Names: bag
UniProt
Find proteins for P27951 (Streptococcus agalactiae)
Explore P27951 
Go to UniProtKB:  P27951
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP27951
Sequence Annotations
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Reference Sequence

Small Molecules

Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
MSE
Query on MSE
A, B
L-PEPTIDE LINKINGC5 H11 N O2 SeMET

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.05 Å
  • R-Value Free:  0.274 (Depositor), 0.275 (DCC) 
  • R-Value Work:  0.243 (Depositor), 0.244 (DCC) 
  • R-Value Observed: 0.246 (Depositor) 
Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 61.734α = 90
b = 79.033β = 90
c = 81.185γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data scaling
HKL-2000data reduction
AutoSolphasing

Structure Validation

View Full Validation Report



Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United StatesR21AI155828

Revision History  (Full details and data files)

  • Version 1.0: 2025-08-27
    Type: Initial release
  • Version 1.1: 2026-08-19
    Changes: Database references