Humans who eat red meat are vulnerable to bacteria that cause food poisoning because their cells incorporate an otherwise foreign sugar molecule found in lamb, pork and beef, new research published in Nature reveals.
Emory University biochemist David Smith, PhD, played a critical role in putting together the research team that made this surprising observation.
“One of the researchers and authors, James C. Paton, from the University of Adelaide in Australia, sent a protein toxin to Emory to be analyzed on our glycan microarray,” explains Smith.
The Australian researchers were studying subtilase cytotoxin, which comes from certain kinds of E. coli bacteria. Bacterial production of the toxin and subsequent binding and entry of toxin into intestinal cells causes bloody diarrhea and a potentially fatal disease called haemolytic uraemic syndrome.
The glycan microarray, housed in the Emory Glycomics Center, allows researchers to test whether proteins stick to a large variety of carbohydrate molecules (glycans), which are found on the surface of animal cells.
“When I noticed that this toxin, which was supposed to be toxic to humans, bound tightly to glycans containing N-glycolylneuraminic acid, a non-human carbohydrate," says Smith, "I put Dr. Paton in touch with Ajit Varki, an expert at the University of California San Diego in studies on N-glycolylneuraminic acid. The resulting collaboration is a nice example of how the Emory Glycomics Center and the international Consortium for Functional Glycomics have facilitated discovery.”
The study combines Emory data on which sugars the toxin binds to, animal studies in San Diego, and protein structural studies in Australia.
The Emory Glycomics Center houses the Protein-Carbohydrate Interaction Core H of the Consortium for Functional Glycomics, a research initiative funded by the National Institute of General Medical Sciences of the National Institutes of Health. Smith is the director of Core Facility H.
Reference: “Incorporation of a non-human glycan mediates human susceptibility to a bacterial toxin.” Nature, Advance Online Publication. Emma Byres, Adrienne W. Paton, James C. Paton, Jonas C. Lofling, David F. Smith, Matthew C. J. Wilce, Ursula M. Talbot, Damien C. Chong, Hai Yu, Shengshu Huang, Xi Chen, Nissi M. Varki, Ajit Varki, Jamie Rossjohn and Travis Beddoe.