title: Diatom mimics: directing the formation of biosilica nanoparticles by controlled folding of lysine-leucine peptides.
abstract: Silaffins, long chain polyamines, and other biomolecules found in diatoms are involved in the assembly of a large number of silica nanostructures under mild, ambient conditions. Nanofabrication researchers have sought to mimic the diatom's biosilica production capabilities by engineering proteins to resemble aspects of naturally occurring biomolecules. Such mimics can produce monodisperse biosilica nanospheres, but in vitro production of the variety of intricate biosilica nanostructures that compose the diatom frustule is not yet possible. In this study we demonstrate how LK peptides, composed solely of lysine (K) and leucine (L) amino acids arranged with varying hydrophobic periodicities, initiate the formation of different biosilica nanostructures in vitro. When L and K residues are arranged with a periodicity of 3.5 the α-helical form of the LK peptide produces monodisperse biosilica nanospheres. However, when the LK periodicity is changed to 3.0, corresponding to a 310 helix, the morphology of the nanoparticles changes to elongated rod-like structures. β-strand LK peptides with a periodicity of 2.0 induce wire-like silica morphologies. This study illustrates how the morphology of biosilica can be changed simply by varying the periodicity of polar and nonpolar amino acids.
authors.affiliation: School of Chemical, Biological, and Environmental Engineering, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Joe E
authors.initials: JE
authors.lastname: Baio
authors.forename: Ariel
authors.initials: A
authors.lastname: Zane
authors.forename: Vance
authors.initials: V
authors.lastname: Jaeger
authors.forename: Adrienne M
authors.initials: AM
authors.lastname: Roehrich
authors.forename: Helmut
authors.initials: H
authors.lastname: Lutz
authors.forename: Jim
authors.initials: J
authors.lastname: Pfaendtner
authors.forename: Gary P
authors.initials: GP
authors.lastname: Drobny
authors.forename: Tobias
authors.initials: T
authors.lastname: Weidner
mesh_terms: D000595:Amino Acid Sequence; D017377:Diatoms; D007930:Leucine; D008239:Lysine; D008958:Models, Molecular; D008969:Molecular Sequence Data; D053758:Nanoparticles / Q000737:chemistry*; D057786:Peptidomimetics / Q000737:chemistry*; D011487:Protein Conformation; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D057786:Peptidomimetics; D012822:Silicon Dioxide; D007930:Leucine; D008239:Lysine