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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Algal Proteins / chemistry*
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Algal Proteins / genetics
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Algal Proteins / isolation & purification
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Algal Proteins / metabolism
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Amino Acid Motifs
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Amino Acid Sequence
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Bacterial Proteins / chemistry*
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Bacterial Proteins / genetics
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Bacterial Proteins / isolation & purification
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Bacterial Proteins / metabolism
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Cell Wall / chemistry
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Cell Wall / metabolism
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Chemical Precipitation
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Diatoms / chemistry*
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Diatoms / metabolism
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Hydrogen-Ion Concentration
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Lysine / analogs & derivatives
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Lysine / chemistry
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Mass Spectrometry
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Molecular Sequence Data
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Molecular Weight
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Nuclear Magnetic Resonance, Biomolecular
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Peptides
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Propylamines / chemistry
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Protein Isoforms / chemistry
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Proteins / chemistry*
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Proteins / genetics
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Proteins / isolation & purification
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Proteins / metabolism
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Repetitive Sequences, Amino Acid
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Silicic Acid / chemistry
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Silicic Acid / metabolism*
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Silicon Dioxide / chemistry
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Silicon Dioxide / metabolism*
Substances
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Algal Proteins
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Bacterial Proteins
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Peptides
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Propylamines
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Protein Isoforms
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Proteins
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silaffin 1A
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silaffin 1B
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Silicic Acid
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epsilon N-dimethyllysine
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Silicon Dioxide
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Lysine