Proteins are one of the key players in biological systems for the regulation and control of constructive and destructive processes by the specific interaction with, e.g., nucleic acids, proteins and inorganic molecules. The generation of biominerals, such as sea urchin spicules, is such a protein-controlled process resulting in organic-inorganic hybrid materials. Furthermore, proteins and peptides can also control the synthesis of non-biological inorganic materials, which might be interesting for technical and medical applications. In this context, the molecular recognition of the inorganic phase by organic molecules is of particular importance. However, it is challenging to identify mineral-binding peptide motifs from biological systems as well as for applied bioinspired systems, which regulate the biomineral formation. We compared protein motifs consisting of alternating positively and negatively charged amino acids of two different systems: (i) of natural biomineralization proteins, and (ii) of inorganic-binding peptides derived from phage display. Similar motifs were found in natural biomineralization proteins as well as zinc oxide- and zirconia-binding peptides raising questions of a common design principle based on acidic and basic amino acids for peptides interacting with minerals.
Such inorganic-binding peptides can be applied for the generation of self-assembled, complex bio-templates with a superordinate 3-D structure for the mineralization under soft reaction conditions to generate nanostructured hybrid materials. The benefit of bio-templates is discussed in examples by the direct link between inorganic-binding peptides, biomineralization, and the generation of new materials properties.
 Lemloh, M.L., Altintoprak, K., Wege, C., Weiss, I. M. & Rothenstein, D. Biogenic and Synthetic Peptides with Oppositely Charged Amino Acids as Binding Sites for Mineralization. Materials 10 (2017).