ADVERTISEMENT
2 /3 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Materials

Nacre's Trade Secrets Revealed

Two proteins aid the orderly formation of calcium carbonate crystals that gives pearls and oyster shells their iridescent luster

by Sophie L. Rovner
August 17, 2009 | APPEARED IN VOLUME 87, ISSUE 33

[+]Enlarge
Credit: Science/AAAS
Pif proteins help calcium carbonate crystals form bricklike nacre (as shown in the SEM image), which lines a pearl oyster’s shell.
8733scicon5.gif
Credit: Science/AAAS
Pif proteins help calcium carbonate crystals form bricklike nacre (as shown in the SEM image), which lines a pearl oyster’s shell.

Nacre, the iridescent composite that forms pearls and the lining of some mollusk shells, is composed of layers of bricklike aragonite calcium carbonate crystals embedded in a mortar of chitin and proteins. Nature has been stingy in surrendering the secrets behind nacre’s orderly assemblage, but Japanese researchers have now discovered two proteins that are key to this process (Science, DOI: 10.1126/science.1173793). Hiromichi Nagasawa and colleagues of the University of Tokyo discovered one protein, Pif80, by searching for a protein that preferentially binds aragonite. The researchers determined that Pif80 has its origins in a precursor protein; when cleaved, the precursor releases Pif80 and the second protein, Pif97. When the researchers suppressed production of these proteins in oysters, crystal growth was slow and disordered, and the mollusks were unable to form pearly sheets of nacre. Nagasawa’s team believes that Pif80 and Pif97 form a complex that binds to other proteins and chitin, concentrates calcium carbonate, induces formation of aragonite crystals, and regulates crystal orientation.

X

Article:

This article has been sent to the following recipient:

Leave A Comment

*Required to comment