Coral acid rich protein selects vaterite polymorph in vitro.

Corals and other biomineralizing organisms use proteins and other molecules to form different crystalline polymorphs and biomineral structures. In corals, it's been suggested that proteins such as Coral Acid Rich Proteins (CARPs) play a major role in the polymorph selection of their calcium carbonate (CaCO) aragonite exoskeleton. To date, four CARPs (1-4) have been characterized: each with a different amino acid composition and different temporal and spatial expression patterns during coral developmental stages.