title: Design of 11-residue peptides with unusual biophysical properties: induced secondary structure in the absence of water.
abstract: A series of oligopeptides with beta-forming and adhesive properties, were synthesized and analyzed for adhesion shear strength, secondary structure, and association properties. The sequences contained related hydrophobic core segments varying in length from 5 to 12 residues and flanked by di- or tri-lysine segments. Three remarkable peptides consisting of just 11 residues with hydrophobic core sequences of FLIVI, IGSII, and IVIGS flanked by three lysine residues gave the highest dry adhesion shear strength and displayed unusual biophysical properties in the presence and absence of water. KKKFLIVIKKK had its highest adhesion strength at 2% (w/v) at pH 12.0 and showed the highest adhesion strength after exposure to water (water resistance). Both KKKIGSIIKKK and KKKIVIGSKKK, at 4% (w/v) at pH 12.0, displayed nearly identical dry shear strength values to that with the FLIVI core sequence. The peptide with IGSII core, however, displayed a lower water resistance and the latter, IVIGS, showed no water resistance, completely delaminating upon soaking in water. These are the smallest peptides with adhesive properties reported to date and show remarkable adhesion strength even at lower concentrations of 0.2% (w/v), which corresponds to 1.6 mM. The FLIVI containing peptide adopted a beta-sheet secondary structure in water while the IGSII- and IVIGS-containing sequences folded similarly only in the absence of water. Analytical ultracentrifugation studies showed that when the FLIVI sequence adopts beta-structure in aqueous solution, it associates into a large molecular weight assembly. The random coils of IGSII and IVIGS showed no tendency to associate at any pH.
authors.affiliation: Bio-Materials & Technology Lab, Department of Grain Science and Industry, Department of Biochemistry, Kansas State University, Manhattan, Kansas, USA.
authors.forename: Xiaoqun
authors.initials: X
authors.lastname: Mo
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Hiromasa
authors.forename: Matt
authors.initials: M
authors.lastname: Warner
authors.forename: Ahlam N
authors.initials: AN
authors.lastname: Al-Rawi
authors.forename: Takeo
authors.initials: T
authors.lastname: Iwamoto
authors.forename: Talat S
authors.initials: TS
authors.lastname: Rahman
authors.forename: Xiuzhi
authors.initials: X
authors.lastname: Sun
authors.forename: John M
authors.initials: JM
authors.lastname: Tomich
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D001665:Binding Sites; D055592:Biophysical Phenomena; D001703:Biophysics; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012996:Solutions / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D014461:Ultracentrifugation; D014867:Water / Q000737:chemistry*
chemical_list: D010455:Peptides; D012996:Solutions; D014867:Water