title: Statherin: a major boundary lubricant of human saliva.
abstract: The lubricating properties of human submandibular-sublingual salivary fractions were examined using a servohydraulic model of mandibular movement. Fractions containing statherin exhibited a strong tendency to boundary lubrication. The lubricity of purified statherin was confirmed and compared to the amphipathic molecules gramacidin S and sodium dodecyl sulfate. Contact angle measurements of statherin paralleled the other amphipathic molecules. The helical content of statherin increased in trifluoroethanol indicating the presence of amphipathic helical regions. CD studies and hydrophobic moment calculations indicated that statherin adopts an amphipathic helical conformation at the N-terminus. An energy-minimized model of the polar N-terminal residues 1-15 suggested that this domain could be positioned in space to interact with a hydroxyapatite substrate. These data imply that under appropriate conditions statherin may display an amphipathic nature which enables it to function as a boundary lubricant on enamel.
authors.affiliation: Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, School of Dentistry, Minneapolis 55455.
authors.forename: W H
authors.initials: WH
authors.lastname: Douglas
authors.forename: E S
authors.initials: ES
authors.lastname: Reeh
authors.forename: N
authors.initials: N
authors.lastname: Ramasubbu
authors.forename: P A
authors.initials: PA
authors.lastname: Raj
authors.forename: K K
authors.initials: KK
authors.lastname: Bhandary
authors.forename: M J
authors.initials: MJ
authors.lastname: Levine
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D002942:Circular Dichroism; D005260:Female; D006096:Gramicidin / Q000737:chemistry; D006801:Humans; D008153:Lubrication; D008969:Molecular Sequence Data; D012463:Saliva / Q000737:chemistry*; D012471:Salivary Proteins and Peptides / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013329:Structure-Activity Relationship; D013361:Sublingual Gland / Q000737:chemistry; D013363:Submandibular Gland / Q000737:chemistry
chemical_list: C018149:STATH protein, human; D012471:Salivary Proteins and Peptides; D006096:Gramicidin; D012967:Sodium Dodecyl Sulfate