Self-Assembly of Highly Phosphorylated Silaffins and Their Function in Biosilica Morphogenesis
Nils Kröger,1
Sonja Lorenz,2
Eike Brunner,2
Manfred Sumper1*
Silaffins are uniquely modified peptides that have been
implicated in the biogenesis of diatom biosilica. A method that avoids the harsh anhydrous hydrogen fluoride treatment commonly used to
dissolve biosilica allows the extraction of silaffins in their native
state. The native silaffins carry further posttranslational modifications in addition to their polyamine moieties. Each serine residue was phosphorylated, and this high level of
phosphorylation is essential for biological activity. The
zwitterionic structure of native silaffins enables the formation of
supramolecular assemblies. Time-resolved analysis of silica
morphogenesis in vitro detected a plastic silaffin-silica phase, which
may represent a building material for diatom biosilica.
1 Lehrstuhl Biochemie I,
2 Institut für Biophysik und Physikalische
Biochemie, Universität Regensburg, 93053 Regensburg, Germany.
*
To whom correspondence should be addressed. E-mail:
manfred.sumper{at}vkl.uni-regensburg.de
