Polymorphic carbonate in fish otoliths
Polymorphic carbonate in fish otoliths
Many organisms exhibit astonishing biomineralization abilities, forming polymorphic minerals from the same chemical substance. Fish inner ear otoliths consist of calcium carbonate (CaCO3) in various polymorphic forms (e.g., vaterite, aragonite). Proteins are known to be involved in controlling polymorphic forms, with a new study suggesting a mechanism involving phosphorylation of a protein responsible of biomineralisation. Phosphorylation corresponds to calcium carbonate crystallizing as vaterite, whereas its absence leads to calcite precipitation.
Figure: An experiment suggesting different biomineralization activity of a Starmaker-like protein (from fish otoliths), which in its phosphorylated form influences the formation of vaterite, whereas it promotes the formation of calcitic calcium carbonate crystals if it is in a dephosphorylated form.
PUBLICATION: Kalka, M., Bielak, K., Ptak, M., Stolarski, J., Dobryszycki, P., Wojtas, M. 2024. Calcium carbonate polymorph selection in fish otoliths: a key role of phosphorylation of Starmaker-like protein. Acta Biomaterialia 174: 437-446, doi: 10.1016/j.actbio.2023.11.039