Threonine and Polythreonine Accelerate Calcium Carbonate Formation

Acidic macromolecules are considered to be critical to calcium carbonate formation in organisms and have been chosen as a model chemical for modifying biomineralization. Here, this view is challenged, and it is found that low-charge amino acid threonine (Thr) and its polymer poly-Thr can accelerate calcium carbonate formation by increasing nucleation. In contrast to aspartic acid (Asp) and poly-Asp, Thr and poly-Thr did not affect the morphology of product crystals but accelerated the formation of crystal nucleation rapidly. This effect may be partially attributed to the negative charges of these chemicals that interact with calcium. This finding provides novel insights into the mechanisms of biomineralization that involve diverse chemistry control not limited to acidic macromolecules and may inspire the synthesis of calcium carbonate in a short time.