Question

The articles that I've been able to find on the structure of abalone shells mention that they consist of calcium carbonate plates connected by proteins, but don't name the proteins. These proteins are key to the shell's strength. What proteins connect the calcium carbonate plates to give the shell its strength? What other proteins are they related to (if any), both structurally and phylogenetically?

I searched via DuckDuckGo using phrases such as abalone shell protein, abalone shell structure protein and abalone shell structure calcium carbonate protein. The best match I found on proteins was In-depth proteomic analyses of Haliotis laevigata (greenlip abalone) nacre and prismatic organic shell matrix; while it names many proteins, it doesn't identify their function.

Answer 1

Abalone shells are composed of calcium carbonate nacre plates bound by proteins such as perlucin and pearlin, which are related to other biomineralization proteins. These proteins provide strength and resilience to the shell, which is sensitive to ocean acidification effects on aragonite formation.

Step-by-step explanation:

The structure of abalone shells is a prime example of the fascinating intersection between biology and chemistry. These shells consist of calcium carbonate plates, known scientifically as nacre, which are connected by a matrix of shell proteins. While research provides a wealth of protein names involved in shell formation, specific proteins that contribute to the shell's strength include members of the perlucin, pearlin, and lustrin families, among others. These proteins act like a glue binding the calcium carbonate plates together, which enhances the mechanical strength and resilience of the abalone shell. Structurally and phylogenetically, these proteins are related to other biomineralization proteins found in different mollusks and organisms that produce calcium carbonate or silica structures, such as coccolithophores and diatoms. The shell-building process is sensitive to environmental factors, and ocean acidification, characterized by an increase in H+ concentration, poses a risk as it hinders the absorption of calcium and carbonate ions necessary for strong aragonite formation, which is a crystal form of calcium carbonate.