Active domains of salivary statherin on apatitic surfaces for binding to Fusobacterium nucleatum cells.
Fusobacterium nucleatum can bind to saliva-coated tooth surfaces. However, the nature of the domains of salivary protein that interact with F. nucleatum remains unclear. The ability of individual proteins in human submandibular-sublingual saliva (HSMSL) to bind F. nucleatum cells was examined by dot blot assay; statherin displayed the strongest binding activity. Statherin binding sites were determined based on binding of (125)I-labelled F. nucleatum to statherin-coated hydroxyapatite (sHAP) beads via inhibition assays using synthetic analogous peptide fragments of whole statherin. Analogous peptides corresponding to residues 19-26 and 32-39 of statherin inhibited binding by 77 % and 68 %, respectively. Synthetic peptides were also prepared by serial deletions of individual residues from N- and C-termini of the peptides GPYQPVPE (aa 19-26) and QPYQPQYQ (aa 32-39). The inhibitory effects of peptides YQPVPE (aa 21-26) and PYQPQYQ (aa 33-39) were very similar to those of GPYQPVPE and QPYQPQYQ, respectively. However, additional deletion of residues resulted in significant reduction of the inhibitory effect. Alanine-scan analysis of YQPVPE revealed that all tested peptides retained inhibitory activity; only YAPVPE exhibited significantly decreased inhibitory activity. These findings suggest that YQPVPE and PYQPQYQ may represent the minimal active segments of statherin for binding to F. nucleatum; moreover, Gln may be a key amino acid in the active segment.
Sekine
Shinichi
S
Departments of Preventive Dentistry, Graduate School of Dentistry, Osaka University, Suita, Japan.
Kataoka
Kosuke
K
Departments of Preventive Dentistry, Graduate School of Dentistry, Osaka University, Suita, Japan.
Tanaka
Muneo
M
Departments of Preventive Dentistry, Graduate School of Dentistry, Osaka University, Suita, Japan.
Nagata
Hideki
H
Departments of Preventive Dentistry, Graduate School of Dentistry, Osaka University, Suita, Japan.
Kawakami
Toru
T
Institute for Protein Research, Osaka University, Suita, Japan.
Akaji
Kenichi
K
Institute for Protein Research, Osaka University, Suita, Japan.
Aimoto
Saburo
S
Institute for Protein Research, Osaka University, Suita, Japan.
Shizukuishi
Satoshi
S
Departments of Preventive Dentistry, Graduate School of Dentistry, Osaka University, Suita, Japan.
D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001665:Binding Sites; D017886:Durapatite / Q000737:chemistry*; D016967:Fusobacterium nucleatum / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D012463:Saliva / Q000737:chemistry*; D012471:Salivary Proteins and Peptides / Q000737:chemistry* / Q000378:metabolism
D010446:Peptide Fragments; C018149:STATH protein, human; D012471:Salivary Proteins and Peptides; D017886:Durapatite