Tooth decay enzyme identified, targeted

07 Dec 2010



Once the sugar chains are attached to your teeth, they ferment -- releasing acids that dissolve the calcium in your teeth, creating cavities.

The biologists used protein crystallography to work out the three-dimensional structure of the enzyme, revealing details about its folding mechanism, which allowed them to get insight about how it functions. It was already known that the enzyme splits sucrose into fructose and glucose, and then added the glucose molecules to the sugar chain, but it was assumed that these took place in different parts of the enzyme. That turns out not to be true -- the researchers proved that both activities take place in the same active site of the enzyme.

The interesting part comes when the researchers discuss inhibiting that enzyme -- meaning that the bacteria is unable to attach to the tooth enamel, potentially eradicating plaque.

However, the process isn't as easy as it sounds -- there's a very similar, and very crucial, enzyme in saliva called amylase, which degrades starch for digestion. Potential inhibitors have so far taken that enzyme out alongside the glucansucrase enzyme. A more precisely-targeted weapon is needed.

Dijkhuizen pointed out: "The crystal structure revealed that the active sites are virtually identical. Future inhibitors thus need to be directed towards very specific targets because both enzymes are evolutionary closely related."

If that inhibitor can be found, however, it paves the way for a future where glucansucrase inhibitors can be added to toothpaste or mouthwash. "It may even be possible to add them to sweets", suggested Dijkhuizen.