Researcher Nathalie Juge of the Institute of Food Research in Norwich, England, said the protein could be used to identify probiotics likely to be of benefit to people.
"Probiotics need to interact with cells lining the gut to have a beneficial effect, and if they attach to surfaces in the gut they are more likely to stick around long enough to exert their activity," Juge said, noting the gut is the largest immune system organ in the body.
Mucus adhesion has been well studied for pathogenic bacteria, but exactly what enables gut bacteria to stick is not known. The research by Institute of Food Research and University of East Anglia scientists has produced the first crystal structure of a mucus-binding protein.
The team of scientists said they found the mucus-binding proteins recognize human immunoglobulin proteins that are an integral part of the immune system and might therefore play a wider role in gut health as a site for attachment of bacteria.
"The strain-specificity of these proteins demonstrates the need for the careful molecular design and selection of probiotics," Juge said. "This also opens new avenues of research to study the fundamental roles bacteria play in the gastrointestinal tract."
The research appears in the Journal of Biological Chemistry.