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Document Version Version Comment Date Status
732401.0 Automatic journal name synchronization 29.04.2017 20:16 Released

ID: 732401.0, MPI für molekulare Zellbiologie und Genetik / MPI-CBG Publications 2016 (archival)
Biochemical Composition and Assembly of Biosilica-associated Insoluble Organic Matrices from the Diatom Thalassiosira pseudonana.
Authors:Kotzsch, Alexander; Pawolski, Damian; Milentyev, Alexander; Shevchenko, Anna; Scheffel, André; Poulsen, Nicole; Shevchenko, Andrej; Kröger, Nils
Date of Publication (YYYY-MM-DD):2016
Title of Journal:The Journal of Biological Chemistry
Issue / Number:10
Start Page:4982
End Page:4997
Copyright:not available
Audience:Experts Only
Intended Educational Use:No
Abstract / Description:The nano- and micropatterned biosilica cell walls of diatoms are remarkable examples of biological morphogenesis and possess highly interesting material properties. Only recently has it been demonstrated that biosilica-associated organic structures with specific nanopatterns (termed insoluble organic matrices) are general components of diatom biosilica. The model diatom Thalassiosira pseudonana contains three types of insoluble organic matrices: chitin meshworks, organic microrings, and organic microplates, the latter being described in the present study for the first time. To date, little is known about the molecular composition, intracellular assembly, and biological functions of organic matrices. Here we have performed structural and functional analyses of the organic microrings and organic microplates from T. pseudonana. Proteomics analysis yielded seven proteins of unknown function (termed SiMat proteins) together with five known silica biomineralization proteins (four cingulins and one silaffin). The location of SiMat1-GFP in the insoluble organic microrings and the similarity of tyrosine- and lysine-rich functional domains identifies this protein as a new member of the cingulin protein family. Mass spectrometric analysis indicates that most of the lysine residues of cingulins and the other insoluble organic matrix proteins are post-translationally modified by short polyamine groups, which are known to enhance the silica formation activity of proteins. Studies with recombinant cingulins (rCinY2 and rCinW2) demonstrate that acidic conditions (pH 5.5) trigger the assembly of mixed cingulin aggregates that have silica formation activity. Our results suggest an important role for cingulins in the biogenesis of organic microrings and support the hypothesis that this type of insoluble organic matrix functions in biosilica morphogenesis.
External Publication Status:published
Document Type:Article
Version Comment:Automatic journal name synchronization
Communicated by:Thüm
Affiliations:MPI für molekulare Zellbiologie und Genetik