Catalyzes the polymerization of silica spheres from a silicilic acid solution. It therefore plays a central role in the formation of silica cell wall of diatoms. Silaffin-1A peptides form large aggregates via electrostatic interactions due to intermolecular interactions between the negatively charged phosphate groups and the polyamine moieties. It is unknown whether the acidic chain located at the N-terminus is functional or whether it represents a propeptide. N6-polymethylaminopropylated. Two lysine residues of each peptide bears 6 to 11 repeats of methyl-propylamine, which gives a possible template for nucleation, and may also control the silica colloid size within the silica deposition vesicle (SDV). Phosphorylated. All serine residues of the Silaffin-1A1 peptide are phosphorylated. Only minor amounts of the Silaffin-1A2 peptide are phosphorylated. Phosphorylation is essential for the activity. It may represent a source of anions required for silica formation of diatoms. Due to its ability to synthesize simple silica nanospheres in vitro from silanes at nearly neutral pH and at ambient temperatures and pressures, it is of great interest in nanotechnology. May be of practical use for the fabrication of photonic devices. The results of the mass spectrometry differ for the same peptide due to the length of the methyl-propylamine chains that vary from 14 to 18 units for the Silaffin-1A2 peptide (141-158) and from 13 to 17 units for the Silaffin-1A1 peptide (163-177). The species-specific pattern of biosilica pattern of diatoms may be generated by polyamines of different chain lengths as well as by a synergistic action of long-chain polyamines and silaffins. Miniature masonry - Issue 43 of February 2004