3QE5

Complete structure of Streptococcus mutans Antigen I/II carboxy-terminus


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.208 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal Structure of the C-terminal Region of Streptococcus mutans Antigen I/II and Characterization of Salivary Agglutinin Adherence Domains.

Larson, M.R.Rajashankar, K.R.Crowley, P.J.Kelly, C.Mitchell, T.J.Brady, L.J.Deivanayagam, C.

(2011) J.Biol.Chem. 286: 21657-21666

  • DOI: 10.1074/jbc.M111.231100

  • PubMed Abstract: 
  • The Streptococcus mutans antigen I/II (AgI/II) is a cell surface-localized protein that adheres to salivary components and extracellular matrix molecules. Here we report the 2.5 Å resolution crystal structure of the complete C-terminal region of AgI/ ...

    The Streptococcus mutans antigen I/II (AgI/II) is a cell surface-localized protein that adheres to salivary components and extracellular matrix molecules. Here we report the 2.5 Å resolution crystal structure of the complete C-terminal region of AgI/II. The C-terminal region is comprised of three major domains: C(1), C(2), and C(3). Each domain adopts a DE-variant IgG fold, with two β-sheets whose A and F strands are linked through an intramolecular isopeptide bond. The adherence of the C-terminal AgI/II fragments to the putative tooth surface receptor salivary agglutinin (SAG), as monitored by surface plasmon resonance, indicated that the minimal region of binding was contained within the first and second DE-variant-IgG domains (C(1) and C(2)) of the C terminus. The minimal C-terminal region that could inhibit S. mutans adherence to SAG was also confirmed to be within the C(1) and C(2) domains. Competition experiments demonstrated that the C- and N-terminal regions of AgI/II adhere to distinct sites on SAG. A cleft formed at the intersection between these C(1) and C(2) domains bound glucose molecules from the cryo-protectant solution, revealing a putative binding site for its highly glycosylated receptor SAG. Finally, electron microscopy images confirmed the elongated structure of AgI/II and enabled building a composite tertiary model that encompasses its two distinct binding regions.


    Organizational Affiliation

    Department of Physiology and Biophysics, University of Alabama, Birmingham, Alabama 35294, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Major cell-surface adhesin PAc
A, B
516Streptococcus mutansMutation(s): 0 
Gene Names: pac
Find proteins for P11657 (Streptococcus mutans)
Go to UniProtKB:  P11657
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A, B
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
GLC
Query on GLC

Download SDF File 
Download CCD File 
A, B
ALPHA-D-GLUCOSE
C6 H12 O6
WQZGKKKJIJFFOK-DVKNGEFBSA-N
 Ligand Interaction
MG
Query on MG

Download SDF File 
Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.208 
  • Space Group: I 2 2 2
Unit Cell:
Length (Å)Angle (°)
a = 108.495α = 90.00
b = 156.360β = 90.00
c = 213.648γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
HKL-2000data reduction
SHARPphasing
HKL-2000data scaling
HKL-2000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-04-20
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance