Polycationic Peptides from Diatom Biosilica That Direct Silica Nanosphere Formation
Nils Kröger,
*
Rainer Deutzmann,
Manfred Sumper
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
-N,N-dimethyl-
lysine. These modifications drastically influence the
silica-precipitating activity of silaffins.
Lehrstuhl Biochemie I, Universität Regensburg, 93053 Regensburg, Germany.
*
To whom correspondence should be addressed. E-mail:
nils.kroeger{at}vkl.uni-regensburg.de