Inhibition of Streptococcus mutans adherence and biofilm formation using analogues of the SspB peptide

Abstract

Objective Streptococcus gordonii is a pioneer colonizer of the enamel salivary pellicle that forms biofilm on the tooth surfaces. Recent reports show the surface protein analogue peptide {400 (T) of SspB 390–402 is substituted to K forming SspB (390–T400K–402)} from S. gordonii interacts strongly with salivary receptors to cariogenic bacteria, Streptococcus mutans. To characterize the analogue peptide biological activities, we investigated its binding and inhibiting effects, and the role of its amino acid moities. Methods We measured binding activity of analogue peptides to salivary components using the BIAcore assay; assayed inhibition activities of peptides for bacterial binding and growth on saliva-coated hydroxyapatite beads (s-HA); and describe the peptides interfering with biofilm formation of S. mutans on polystyrene surfaces . Results The SspB (390–T400K–402 and –401) peptides significantly bound with salivary components and inhibited the binding of S. mutans and S. gordonii to s-HA without bactericidal activity; but did not inhibit binding of Streptococcus mitis, a beneficial commensal . Further, the lack of D and E-L at position 390 and 401–402 in the peptide, and substituted peptide SspB (D390H– or D390K–T400K–402) did not bind to salivary components or inhibit binding of S. mutans. The SspB (390–T400K–402) peptide inhibited biofilm formation on salivary components-coated polystyrene surfaces in absence of conditioned planktonic cells. Conclusions We found constructing the peptide to include positions 390(D), 400(K) and 401(E), two surface positive and negative connective charges, and at least 12 amino acids are required to bind salivary components and inhibit the binding of S. mutans and S. gordonii.