Differential binding specificities of oral streptococcal antigen I/II family adhesins for human or bacterial ligands
Open Access
- 4 February 2005
- journal article
- Published by Wiley in Molecular Microbiology
- Vol. 55 (5) , 1591-1605
- https://doi.org/10.1111/j.1365-2958.2005.04495.x
Abstract
The antigen I/II (AgI/II) family polypeptides, ranging from 1310 to 1653 amino acid (aa) residues, are cell wall anchored adhesins expressed by most indigenous species of oral streptococci. The polypeptides interact with a wide range of host molecules, in particular salivary agglutinin glycoprotein (SAG or gp340), and with ligands on other oral bacteria. To determine the receptor recognition properties of six different AgI/II family polypeptides from strains of Streptococcus gordonii, Streptococcus intermedius and Streptococcus mutans, the genes were cloned and expressed on the surface of the surrogate host Lactococcus lactis. The S. gordonii SspA and SspB polypeptides mediated higher binding levels of L. lactis cells to surface immobilized gp340 than did S. intermedius Pas protein, or S. mutans SpaP or PAc proteins. However, the AgI/II proteins were all similar in their abilities to mediate aggregation of lactococci by fluid phase gp340. The SpaPI polypeptide from S. mutans Ingbritt, which was C-terminally truncated by approximately 400 aa residues, did not bind gp340. Lactococci expressing AgI/II proteins, including SpaPI, were aggregated by a synthetic 16 aa residue peptide SRCRP2 derived from the aa repeat block sequences within gp340. In coaggregation assays, SspB from S. gordonii was unique in mediating coaggregation with only group A and group E strains of Actinomyces naeslundii. All the other AgI/II polypeptides mediated coaggregation with group C and group D strains of A. naeslundii. Analysis of chimeric protein constructs revealed that coaggregation specificity was determined by sequences within the N-terminal half of AgI/II protein. A synthetic peptide (20 aa residues), which defines a putative adhesion epitope within the C-terminal region of polypeptide, inhibited AgI/II-mediated aggregation by gp340 but did not affect coaggregation with A. naeslundii. These results suggest that different mechanisms operate in interactions of AgI/II family polypeptides with native gp340, gp340 SRCR domain peptide, and A. naeslundii. Specificity of these interactions appears to be determined by discontinuous but interacting regions of the polypeptides, thus providing flexibility in receptor recognition for streptococcal colonization of the human host.Keywords
This publication has 82 references indexed in Scilit:
- An amino‐terminal domain of Enterococcus faecalis aggregation substance is required for aggregation, bacterial internalization by epithelial cells and binding to lipoteichoic acidMolecular Microbiology, 2004
- Characterization of the Conformational Epitope of Guy's 13, a Monoclonal Antibody That Prevents Streptococcus mutans Colonization in HumansInfection and Immunity, 2003
- Construction of a Novel Transposon Mutagenesis System Useful in the Isolation of Streptococcus parasanguis Mutants Defective in Fap1 GlycosylationInfection and Immunity, 2002
- Structural and Functional Variation within the Alanine-Rich Repetitive Domain of Streptococcal Antigen I/IIInfection and Immunity, 2002
- Crystal Structure of the V-region of Streptococcus mutans Antigen I/II at 2.4Å Resolution Suggests a Sugar Preformed Binding SiteJournal of Molecular Biology, 2002
- Functional Variation of the Antigen I/II Surface Protein in Streptococcus mutans and Streptococcus intermediusInfection and Immunity, 2002
- Mutualism versus Independence: Strategies of Mixed-Species Oral Biofilms In Vitro Using Saliva as the Sole Nutrient SourceInfection and Immunity, 2001
- Expression and Functional Properties of the Streptococcus intermedius Surface Protein Antigen I/IIInfection and Immunity, 2001
- Improved cloning vectors and transformation procedure for Lactococcus lactisJournal of Applied Bacteriology, 1993
- Mutants of Streptococcus gordonii Challis over-producing glucosyltransferaseJournal of General Microbiology, 1991