Simple amino acid key to tooth enamel strength

A simple amino acid that is repeated in the center of proteins found in tooth enamel makes teeth stronger and more resilient, according to new research conducted at the University of Illinois at Chicago.

The findings were published in the December 21 online version of PLoS Biology. Tom Diekwisch, D.M.D., Ph.D., professor and head of oral biology in the UIC College of Dentistry and his team compared proline repeats in amphibian and animal models and discovered that when the repeats are short, such as in frogs, teeth will not have the enamel prisms that are responsible for the strength of human enamel.

In contrast, when the proline repeats are long, they contract groups of molecules that help enamel crystals grow. "Proline repeats are amazing," said Dr. Diekwisch in a university press release. "They hold the key to understanding the structure and function of many natural proteins, including mucins, antifreeze proteins, Alzheimer amyloid, and prion proteins."

When tooth enamel is grown, it is bathed in bubble-shaped groupings of proteins, Dr. Diekwisch said. The size of the protein bubbles varies in different animals, from 5 nanometers in cows to 20 nanometers in mice and 40 nanometers in frogs.

Dr. Diekwisch's team discovered that the longer the stretch of proline repeats, the more the protein bubbles contracted. The study also showed that the smaller protein bubbles were associated with longer enamel crystals. "We hope that one day these findings will help people replace lost parts of the tooth with a healthy layer of new enamel," he said.