title: Polycationic peptides from diatom biosilica that direct silica nanosphere formation.
abstract: Diatom cell walls are regarded as a paradigm for controlled production of nanostructured silica, but the mechanisms allowing biosilicification to proceed at ambient temperature at high rates have remained enigmatic. A set of polycationic peptides (called silaffins) isolated from diatom cell walls were shown to generate networks of silica nanospheres within seconds when added to a solution of silicic acid. Silaffins contain covalently modified lysine-lysine elements. The first lysine bears a polyamine consisting of 6 to 11 repeats of the N-methyl-propylamine unit. The second lysine was identified as epsilon-N,N-dimethyl-lysine. These modifications drastically influence the silica-precipitating activity of silaffins.
authors.affiliation: Lehrstuhl Biochemie I, Universität Regensburg, 93053 Regensburg, Germany. nils.kroeger@vkl.uni-regensburg.de
authors.forename: N
authors.initials: N
authors.lastname: Kröger
authors.forename: R
authors.initials: R
authors.lastname: Deutzmann
authors.forename: M
authors.initials: M
authors.lastname: Sumper
mesh_terms: D020418:Algal Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism; D011232:Chemical Precipitation; D017377:Diatoms / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000031:analogs & derivatives / Q000737:chemistry; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides; D011437:Propylamines / Q000737:chemistry; D020033:Protein Isoforms / Q000737:chemistry; D011506:Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid; D012824:Silicic Acid / Q000737:chemistry / Q000378:metabolism*; D012822:Silicon Dioxide / Q000737:chemistry / Q000378:metabolism*
chemical_list: D020418:Algal Proteins; D001426:Bacterial Proteins; D010455:Peptides; D011437:Propylamines; D020033:Protein Isoforms; D011506:Proteins; C400535:silaffin 1A; C400536:silaffin 1B; D012824:Silicic Acid; C018926:epsilon N-dimethyllysine; D012822:Silicon Dioxide; D008239:Lysine