A common binding motif for various bacteria of the bacteria-binding peptide SRCRP2 of DMBT1/gp-340/salivary agglutinin

Biol Chem. 2008 Sep;389(9):1193-200. doi: 10.1515/BC.2008.135.


Abstract Salivary agglutinin (DMBT1SAG) is identical to lung glycoprotein-340 and encoded by deleted in malignant brain tumors-1. It is a member of the scavenger receptor cysteine-rich (SRCR) superfamily, proteins that have one or more SRCR domains. Salivary agglutinin plays a role in oral innate immunity by the binding and agglutination of oral streptococci. S. mutans has been shown to bind to a 16-mer peptide (QGRVEVLYRGSWGTVC) located within the SRCR domains. Within this peptide, designated SRCR Peptide 2, residues VEVL and W were critical for binding. The aim of this study was to investigate binding of DMBT1SAG to other bacteria. Therefore, interaction between a series of bacteria and DMBT1(SAG), SRCR peptide 2 and its alanine substitution variants was studied in adhesion and agglutination assays. For different bacteria there was a highly significant correlation between adhesion to DMBT1SAG and adhesion to SRCR peptide 2 suggesting that SRCR peptide 2 is the major bacteria binding site. An alanine substitution scan showed that 8 amino acids were involved in binding (xRVEVLYxxSWxxxx). The binding motifs varied for different species were found, but the residues VxVxY and W were always present. In conclusion, a common binding motif (RVEVLYxxxSW) within the SRCR domains is responsible for the broad bacteria-binding spectrum of DMBT1SAG.

MeSH terms

  • Agglutination
  • Amino Acid Motifs*
  • Bacteria / immunology
  • Bacteria / metabolism*
  • Bacterial Adhesion
  • Binding Sites
  • Calcium-Binding Proteins
  • DNA-Binding Proteins
  • Humans
  • Peptides / chemical synthesis
  • Peptides / chemistry
  • Peptides / immunology
  • Peptides / metabolism
  • Protein Binding
  • Protein Structure, Tertiary
  • Receptors, Cell Surface / chemistry*
  • Receptors, Cell Surface / immunology
  • Receptors, Cell Surface / isolation & purification
  • Receptors, Cell Surface / metabolism*
  • Saliva / immunology
  • Saliva / metabolism*
  • Salivary Proteins and Peptides / chemistry
  • Salivary Proteins and Peptides / immunology
  • Salivary Proteins and Peptides / metabolism
  • Static Electricity
  • Streptococcus mutans / immunology
  • Streptococcus mutans / metabolism*
  • Tumor Suppressor Proteins


  • Calcium-Binding Proteins
  • DMBT1 protein, human
  • DNA-Binding Proteins
  • Peptides
  • Receptors, Cell Surface
  • Salivary Proteins and Peptides
  • Tumor Suppressor Proteins