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Abstract

Limpets are marine mollusks using mineralized teeth, one of the hardest and strongest biomaterials, to feed on algae on intertidal rocks. However, most of studies only focuses on the ultrastructure and chemical composition of the teeth while the molecular information is largely unknown, limiting our understanding of this unique and fundamental biomineralization process. In this study, we investigated the microstructure, proteomics and crystallization in the teeth of limpet Cellana toreuma. It is found that the limpets formed alternatively tricuspid teeth and unicuspid teeth. Small nanoneedles were densely packed at the tips or leading regions of the cusps. In contrast, big nanoneedles resembling chemical synthesized goethite were loosely packed in the trailing regions of the cusps. Proteins extracted from the whole radula such as ferritin, peroxiredoxin, arginine kinase, GTPase-Rabs and clathrin were identified by proteomics. Goethite-binding experiment coupled with proteomics and RNA-seq highlighted six chitin-binding proteins (CtCBPs). Furthermore, the extracted proteins from the cusps of radula or the framework chitin induced packing of crystals and possibly affected crystal polymorphs in vitro. This study provides insight into the unique biomineralization process in the limpet teeth at the molecular levels, which may guide biomimetic strategies aimed at designing hard materials at room temperature.