Dynamic force spectroscopy of the Helicobacter pylori BabA–Lewis b Binding

The binding strength of the Helicobacter pylori adhesin–receptor complex BabA-ABO/Lewis b has been analyzed by means of dynamic force spectroscopy. High-resolution measurements of rupture forces were performed in situ on single bacterial cells, expressing the high-affinity binding BabA adhesin, by the use of force measuring optical tweezers. The resulting force spectra revealed the mechanical properties of a single BabA–Leb bond. It was found that the bond is dominated by one single energy barrier and that it is a slip-bond. The bond length and thermal off-rate were assessed to be 0.86 ± 0.07 nm and 0.015 ± 0.006 s− 1, respectively.