2O0I

crystal structure of the R185A mutant of the N-terminal domain of the Group B Streptococcus Alpha C protein


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.10 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.245 
  • R-Value Observed: 0.247 

wwPDB Validation   3D Report Full Report


This is version 1.5 of the entry. See complete history


Literature

Identification of a glycosaminoglycan binding region of the alpha C protein that mediates entry of group B streptococci into host cells.

Baron, M.J.Filman, D.J.Prophete, G.A.Hogle, J.M.Madoff, L.C.

(2007) J Biol Chem 282: 10526-10536

  • DOI: https://doi.org/10.1074/jbc.M608279200
  • Primary Citation of Related Structures:  
    2O0I

  • PubMed Abstract: 

    Group B Streptococcus (GBS) frequently colonizes the human gastrointestinal and gynecological tracts and less frequently causes deep tissue infections. The transition between colonization and infection depends upon the ability of the organism to cross epithelial barriers. The alpha C protein (ACP) on the surface of GBS contributes to this process. A virulence factor in mouse models of infection, and prototype for a family of Gram-positive bacterial surface proteins, ACP facilitates GBS entry into human cervical epithelial cells and movement across cell layers. ACP binds to host cell surface glycosaminoglycan (GAG). From crystallography, we have identified a cluster of basic residues (BR2) that is a putative GAG binding area in Domain 2, near the junction of the N-terminal domain of ACP and the first of a series of tandem amino acid repeats. D2-R, a protein construct including this region, binds to cells similarly to full-length ACP. We now demonstrate that the predicted charged BR2 residues confer GAG binding; site-directed mutagenesis of these residues (Arg(172), Arg(185), or Lys(196)) eliminates cell-binding activity of construct D2-R. In addition, we have constructed a GBS strain expressing a variant ACP with a charge-neutralizing substitution at residue 185. This strain enters host cells less effectively than does the wild-type strain and similarly to an ACP null mutant strain. The point mutant strain transcytoses similarly to the wild-type strain. These data indicate that GAG-binding activity underlies ACP-mediated cellular entry of GBS. GBS entry into host cells and transcytosis of host cells may occur by distinct mechanisms.


  • Organizational Affiliation

    Channing Laboratory, Department of Medicine, Brigham & Women's Hospital, Boston, Massachusetts 02115, USA. mbaron@partners.org


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
C protein alpha-antigenA [auth 1]180Streptococcus agalactiae serogroup IaMutation(s): 1 
Gene Names: bca
UniProt
Find proteins for Q02192 (Streptococcus agalactiae serotype Ia (strain ATCC 27591 / A909 / CDC SS700))
Explore Q02192 
Go to UniProtKB:  Q02192
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ02192
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.10 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.245 
  • R-Value Observed: 0.247 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 55.7α = 90
b = 55.7β = 90
c = 277.94γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
MOLREPphasing
REFMACrefinement
PDB_EXTRACTdata extraction
MAR345data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-02-06
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description
  • Version 1.4: 2021-10-20
    Changes: Database references
  • Version 1.5: 2023-08-30
    Changes: Data collection, Refinement description