Through unique evolutionary adaptations, H. pylori is able to evade the antiseptic effect of our stomach acid by hiding within the thick acid-resistant layer of mucus that coats the stomach wall. Once within the mucus layer, the bacterium latches onto sugars naturally found on the stomach wall using its adhesion proteins. This attachment is so effective that the bacterium can resist attempts by the body to 'flush' it away, allowing the pathogen to colonise with impunity.
Using extremely powerful x-rays, the scientists were able to study the interactions between the H. pylori adhesion protein BabA and Lewisb sugars of the gastric mucosa at the atomic level. They found that, right at its tip, BabA possesses a specific groove that enables it to securely attach to Lewisb using a network of hydrogen bonds (the same kind of interactions that keep water molecules together).
The research team also found that this network is finely tuned - if a few of the hydrogen bonds are disrupted, the network doesn't function and binding can no longer occur. This insight into the molecular interactions required for adhesion is a promising lead for the development of new strategies for the treatment of H. pylori infections.