3QC6

GspB


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.215 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

A Structural Model for Binding of the Serine-Rich Repeat Adhesin GspB to Host Carbohydrate Receptors.

Pyburn, T.M.Bensing, B.A.Xiong, Y.Q.Melancon, B.J.Tomasiak, T.M.Ward, N.J.Yankovskaya, V.Oliver, K.M.Cecchini, G.Sulikowski, G.A.Tyska, M.J.Sullam, P.M.Iverson, T.M.

(2011) Plos Pathog. 7: e1002112-e1002112

  • DOI: 10.1371/journal.ppat.1002112
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • GspB is a serine-rich repeat (SRR) adhesin of Streptococcus gordonii that mediates binding of this organism to human platelets via its interaction with sialyl-T antigen on the receptor GPIbα. This interaction appears to be a major virulence determina ...

    GspB is a serine-rich repeat (SRR) adhesin of Streptococcus gordonii that mediates binding of this organism to human platelets via its interaction with sialyl-T antigen on the receptor GPIbα. This interaction appears to be a major virulence determinant in the pathogenesis of infective endocarditis. To address the mechanism by which GspB recognizes its carbohydrate ligand, we determined the high-resolution x-ray crystal structure of the GspB binding region (GspB(BR)), both alone and in complex with a disaccharide precursor to sialyl-T antigen. Analysis of the GspB(BR) structure revealed that it is comprised of three independently folded subdomains or modules: 1) an Ig-fold resembling a CnaA domain from prokaryotic pathogens; 2) a second Ig-fold resembling the binding region of mammalian Siglecs; 3) a subdomain of unique fold. The disaccharide was found to bind in a pocket within the Siglec subdomain, but at a site distinct from that observed in mammalian Siglecs. Confirming the biological relevance of this binding pocket, we produced three isogenic variants of S. gordonii, each containing a single point mutation of a residue lining this binding pocket. These variants have reduced binding to carbohydrates of GPIbα. Further examination of purified GspB(BR)-R484E showed reduced binding to sialyl-T antigen while S. gordonii harboring this mutation did not efficiently bind platelets and showed a significant reduction in virulence, as measured by an animal model of endocarditis. Analysis of other SRR proteins revealed that the predicted binding regions of these adhesins also had a modular organization, with those known to bind carbohydrate receptors having modules homologous to the Siglec and Unique subdomains of GspB(BR). This suggests that the binding specificity of the SRR family of adhesins is determined by the type and organization of discrete modules within the binding domains, which may affect the tropism of organisms for different tissues.


    Organizational Affiliation

    Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Platelet binding protein GspB
X
360Streptococcus gordoniiMutation(s): 1 
Gene Names: gspB
Find proteins for Q939N5 (Streptococcus gordonii)
Go to UniProtKB:  Q939N5
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download SDF File 
Download CCD File 
X
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
CA
Query on CA

Download SDF File 
Download CCD File 
X
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
HDZ
Query on HDZ

Download SDF File 
Download CCD File 
X
NITROGEN MOLECULE
N2
IJGRMHOSHXDMSA-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.215 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 33.338α = 90.00
b = 86.743β = 90.00
c = 117.940γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2011-01-15 
  • Released Date: 2011-08-10 
  • Deposition Author(s): Pyburn, T.M.

Revision History 

  • Version 1.0: 2011-08-10
    Type: Initial release
  • Version 1.1: 2011-08-24
    Type: Data collection