How Helicobacter clings on to our stomach

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The bacterium Helicobacter pylori is a known gastric pathogen and causes the bulk of peptic ulcer and gastric cancer cases. H. pylori can survive in the hostile environment of the stomach by tightly holding on to the stomach mucosa. By doing so, the pathogen avoids the highly acidic gastric juices. Using a protein called BabA, H. pylori binds to the ABO-blood group sugars also present in the gastric mucus layer and underlying cells.

VIB researchers at the VUB have now clarified the structural details of BabA and have aptly called it “a molecular chameleon”. Apparently, BabA can change its affinity for the different ABO-blood group sugars according to their prevalence in the human population. The research group, led by Han Remaut, has identified the residues that steer the protein’s binding preference.

Additionally, the investigators also revealed an important weakness of BabA: a short disulfide-bound loop, critical for adherence. This structural feature is a good target for new therapeutics, since disulfide bonds can be broken by reducing compounds such as N-acetylcystein.