Sweet Bioscience

UC Berkeley professor Carolyn Bertozzi keeps a close watch on carbohydrates, but it's not because she's on a trendy diet. In her chemistry laboratory, Bertozzi pays close attention to the carbohydrates that dot the surface of cells.

Bertozzi, a professor of chemistry and of biochemistry and molecular biology, and her graduate students have devised new chemical tools to uncover how the sugar structures change based on various factors. Someday, their research could aid doctors in diagnosing cancer and other diseases.

"We work at the interface of chemistry and biology," says Bertozzi, a faculty scientist with Lawrence Berkeley National Laboratory (LBNL) and investigator with the Howard Hughes Medical Institute. "The chemical tools we develop allow us to probe these sugars to look at changes in their expression in different types of cells, both healthy and diseased."

A variety of sugars and sugar polymers (oligosaccharides and carbohydrates) are attached to the proteins and fats lodged in the cell wall. These sugars, collectively known as glycans, are involved in cell-cell interactions and infection by viruses, bacteria, and other diseases. As a result, their structure contains clues about the state of the cell itself. For example, glycans change during embryonic development and perhaps, Bertozzi says, even when stem cells differentiate.

While Bertozzi and her students have looked at the latter, they've made the most progress correlating certain glycan structures with cancer and other diseases. It's long been known that glycans harboring unnaturally high levels of sialic acid could indicate that the cell is cancerous. The trick though is observing the sugar structure and the glycosylation process, the addition of sugar molecules to proteins and other molecules. Only then, Bertozzi says, could physicians "look for signs in the sugar that something's wrong."

Read the complete article by David Pescovitz at ScienceMatters.