title: Streptococcus pyogenes antigen I/II-family polypeptide AspA shows differential ligand-binding properties and mediates biofilm formation.
abstract: The streptococcal antigen I/II (AgI/II)-family polypeptides are cell wall-anchored adhesins expressed by most indigenous oral streptococci. Proteins sharing 30-40% overall amino acid sequence similarities with AgI/II-family proteins are also expressed by Streptococcus pyogenes. The S. pyogenes M28_Spy1325 polypeptide (designated AspA) displays an AgI/II primary structure, with alanine-rich (A) and proline-rich (P) repeats flanking a V region that is projected distal from the cell. In this study it is shown that AspA from serotype M28 S. pyogenes, when expressed on surrogate host Lactococcus lactis, confers binding to immobilized salivary agglutinin gp-340. This binding was blocked by antibodies to the AspA-VP region. In contrast, the N-terminal region of AspA was deficient in binding fluid-phase gp-340, and L. lactis cells expressing AspA were not agglutinated by gp-340. Deletion of the aspA gene from two different M28 strains of S. pyogenes abrogated their abilities to form biofilms on saliva-coated surfaces. In each mutant strain, biofilm formation was restored by trans complementation of the aspA deletion. In addition, expression of AspA protein on the surface of L. lactis conferred biofilm-forming ability. Taken collectively, the results provide evidence that AspA is a biofilm-associated adhesin that may function in host colonization by S. pyogenes.
authors: School of Oral and Dental Sciences, University of Bristol, Bristol BS12LY, UK.
authors: Sarah E
authors: SE
authors: Maddocks
authors: Christopher J
authors: CJ
authors: Wright
authors: Angela H
authors: AH
authors: Nobbs
authors: Jane L
authors: JL
authors: Brittan
authors: Linda
authors: L
authors: Franklin
authors: Nicklas
authors: N
authors: Strömberg
authors: Aras
authors: A
authors: Kadioglu
authors: Mark A
authors: MA
authors: Jepson
authors: Howard F
authors: HF
authors: Jenkinson
mesh_terms: D018829:Adhesins, Bacterial / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D017353:Gene Deletion; D005816:Genetic Complementation Test; D013294:Lactococcus lactis / Q000235:genetics; D011485:Protein Binding; D025941:Protein Interaction Mapping; D012471:Salivary Proteins and Peptides / Q000378:metabolism; D013297:Streptococcus pyogenes / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D012471:Salivary Proteins and Peptides