Polycationic Peptides from Diatom Biosilica That Direct Silica Nanosphere Formation

• Published in: Science (American Association for the Advancement of Science) Vol. 286; no. 5442; pp. 1129 - 1132
• Main Authors: Kröger, Nils, Deutzmann, Rainer, Sumper, Manfred
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 05.11.1999; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Algae; Algal Proteins - chemistry; Algal Proteins - genetics; Algal Proteins - isolation & purification; Algal Proteins - metabolism; Ambient temperature; Amino Acid Motifs; Amino Acid Sequence; Amino acids; Bacillariophyta; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - isolation & purification; Bacterial Proteins - metabolism; Biological and medical sciences; Cell differentiation; Cell physiology; Cell Wall - chemistry; Cell Wall - metabolism; Cell walls; Chemical Precipitation; Chemistry; Diatoms; Diatoms - chemistry; Diatoms - metabolism; Earth sciences; Earth, ocean, space; Electrons; Exact sciences and technology; Fractions; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Libraries; Lysine - analogs & derivatives; Lysine - chemistry; Marine; Mass Spectrometry; Molecular Sequence Data; Molecular Structure; Molecular Weight; Molecules; Nuclear Magnetic Resonance, Biomolecular; Paleobotany; Paleontology; Peptide synthesis; Peptides; Plant physiology and development; Polyamines; Propylamines - chemistry; Protein Isoforms - chemistry; Proteins; Proteins - chemistry; Proteins - genetics; Proteins - isolation & purification; Proteins - metabolism; Repetitive Sequences, Amino Acid; Scientific Concepts; Sequencing; Silica; Silicic Acid - chemistry; Silicic Acid - metabolism; Silicides; Silicon Dioxide - chemistry; Silicon Dioxide - metabolism; Synthesis; Peptides; Molecular structure; Algae; Nanostructure; Structure function relationship; Silica; Biological activity; Cell wall; Silicification; Heterokontophyta; Bacillariophyta; Ultrastructure; Thallophyta
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.286.5442.1129

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 ε-N,N-dimethyl-lysine. These modifications drastically influence the silica-precipitating activity of silaffins.