Polycationic Peptides from Diatom Biosilica That Direct Silica Nanosphere Formation

American Association for the Advancement of Science (AAAS) - Tập 286 Số 5442 - Trang 1129-1132 - 1999
Nils Kröger1, Rainer Deutzmann1, Manfred Sumper1
1Lehrstuhl Biochemie I, Universität Regensburg, 93053 Regensburg, Germany.

Tóm tắt

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

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We thank G. Lehmann and E. Hochmuth for technical assistance; T. Maurer and H. R. Kalbitzer for NMR analysis; and F. Siedler and H. Sarioglou for MS/MS analysis. We are indebted to G. Wanner for field-emission SEM analysis and R. Wetherbee for help with TEM analysis. We greatfully acknowledge W. Tanner for critically reading the manuscript. This work was supported by the Deutsche Forschungsgemeinschaft (SFB 521).