2WD6

Crystal structure of the Variable Domain of the Streptococcus gordonii Surface Protein SspB


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.176 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal Structure of the Variable Domain of the Streptococcus Gordonii Surface Protein Sspb.

Forsgren, N.Lamont, R.J.Persson, K.

(2009) Protein Sci. 18: 1896

  • DOI: 10.1002/pro.200

  • PubMed Abstract: 
  • The Antigen I/II (AgI/II) family of proteins are cell wall anchored adhesins expressed on the surface of oral streptococci. The AgI/II proteins interact with molecules on other bacteria, on the surface of host cells, and with salivary proteins. Strep ...

    The Antigen I/II (AgI/II) family of proteins are cell wall anchored adhesins expressed on the surface of oral streptococci. The AgI/II proteins interact with molecules on other bacteria, on the surface of host cells, and with salivary proteins. Streptococcus gordonii is a commensal bacterium, and one of the primary colonizers that initiate the formation of the oral biofilm. S. gordonii expresses two AgI/II proteins, SspA and SspB that are closely related. One of the domains of SspB, called the variable (V-) domain, is significantly different from corresponding domains in SspA and all other AgI/II proteins. As a first step to elucidate the differences among these proteins, we have determined the crystal structure of the V-domain from S. gordonii SspB at 2.3 A resolution. The domain comprises a beta-supersandwich with a putative binding cleft stabilized by a metal ion. The overall structure of the SspB V-domain is similar to the previously reported V-domain of the Streptococcus mutans protein SpaP, despite their low sequence similarity. In spite of the conserved architecture of the binding cleft, the cavity is significantly smaller in SspB, which may provide clues about the difference in ligand specificity. We also verified that the metal in the binding cleft is a calcium ion, in concurrence with previous biological data. It was previously suggested that AgI/II V-domains are carbohydrate binding. However, we tested that hypothesis by screening the SspB V-domain for binding to over 400 glycoconjucates and found that the domain does not interact with any of the carbohydrates.


    Organizational Affiliation

    Department of Odontology, Umeå University, Umeå, Sweden.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
AGGLUTININ RECEPTOR
A, B
349Streptococcus gordoniiMutation(s): 0 
Gene Names: ssp5 (sspB)
Find proteins for P16952 (Streptococcus gordonii)
Go to UniProtKB:  P16952
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K

Download SDF File 
Download CCD File 
B
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
GOL
Query on GOL

Download SDF File 
Download CCD File 
A, B
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 
A, B
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.176 
  • Space Group: P 65
Unit Cell:
Length (Å)Angle (°)
a = 110.170α = 90.00
b = 110.170β = 90.00
c = 121.490γ = 120.00
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
PHENIXphasing
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-07-28
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Version format compliance
  • Version 1.2: 2018-01-17
    Type: Data collection